Clay preparation

Reclaiming Your Clay: Worth It, or Not?

Every trimming, every collapsed pot and every bucket of slurry is clay you already paid for. Reclaiming it is free material, a genuine chore, and occasionally a way to ruin a kiln load. Here is the honest accounting, the method that works, and the one contaminant that matters more than all the others.

Dry the scraps out completely, slake them in water, let the excess water off on plaster, then slam wedge. It is free clay at the cost of your time. The only thing that genuinely ruins a batch is plaster getting into it.

The honest pros and cons The contaminant that matters Three videos, none of them ours
The seven step route Is it worth your time Three things that go wrong
Buckets of clay scraps slaking in water beside a plaster bat of drying reclaim
Jump to a section
Is it worth it? The method that works Plaster, the one that matters Mixing clay bodies Why reclaim often throws better Mold, smell and how long it keeps How it works here What goes wrong The whole idea, quickly The route that works Three things that go wrong Questions we get asked Keep going

The honest accounting, the method, and the contaminant that ruins batches.

The whole idea

Clay does not wear out

Unfired clay is completely reversible. A collapsed pot, a bucket of trimmings and yesterday's slurry are all the same material as a fresh bag, just at different water contents.

So reclaiming is not recycling in the usual sense. Nothing is being downgraded. You are moving water around until the clay is back at throwing consistency.

Which makes the whole question an economic one rather than a technical one. The clay is free. Your time is not.

Start to finish

The route that works

How To: Reclaim Your Clay Hot Clay
  1. Let the scraps dry out completely. Bone dry. This is the step people skip and it is the one that makes everything after it easy.
  2. Break them up small and put them in a bucket.
  3. Cover with water and leave it. Dry clay collapses into slurry on its own. A day is usually enough; there is nothing to stir.
  4. Pour off the water that sits on top once it has settled.
  5. Spread it on plaster and leave it until it pulls away from the surface and feels like clay rather than mud.
  6. Slam wedge it, fifteen to twenty cuts, because reclaim is never one consistency.
  7. Spiral wedge to finish, then use it or bag it.

Drying first is not optional. Wet scraps thrown into a bucket turn into a lumpy mess that takes far longer to sort out.

If it went wrong

Three things that go wrong

Plaster got into it

The only genuinely unfixable contamination. A chip of plaster in a pot absorbs water, expands at temperature, and blows a crater out of the wall. It happens weeks later, in the kiln, to a piece you liked.

You skipped the drying step

Wet scraps in a bucket do not slake. They sit as lumps in muddy water and take days of work to bring together. Dry first, always.

You mixed clay bodies without meaning to

Different clays have different shrinkage and different firing ranges. A blend can craze, warp, or in the worst case slump in the kiln. Keep bodies separate.

The honest accounting

Is it actually worth it?

Reclaiming gets treated as a moral obligation. It is really a trade, and the trade is different for different people.

  1. The clay is genuinely free. Not discounted: free. You already bought it, and unfired clay loses nothing by being reprocessed.
  2. The time is not free. Drying, slaking, drying again and wedging is spread over days, and the wedging at the end is real work. Per pound, a bag of fresh clay costs a few dollars.
  3. Doing nothing costs you too. Buckets of scrap take up space, grow mold, and eventually get thrown out. Somebody deals with it either way.
  4. It is better for beginners than they expect. Reclaim is usually softer and more plastic than fresh clay, which is easier to center and more forgiving to pull.
  5. It is worse for anything that has to match. Consistency varies batch to batch, so a set of six mugs is not the place for it.
  6. The environmental argument is real but small. Clay is mined and shipped, and reclaiming reduces both. It is a good reason on top of the others rather than the main one.

The version most people land on

Reclaim your own trimmings because they are clean, known and right there. Do not agonize about the communal slop bucket, which is somebody's job and not necessarily yours. And if you are making something that has to come out exactly right, use fresh clay.

Doing it

The method that works

There are several systems. This is the one that needs the least equipment and the least attention.

The Easiest Way to make Plaster Reclaim Bats // clay reclaim system Pottery to the People Eighteen minutes on building the system rather than just describing it, which is the part most guides skip.
  1. Dry everything first, to bone dry. Spread trimmings out rather than piling them. Dry clay slakes down in hours; damp clay sits in lumps for days.
  2. Break it into small pieces. Smaller pieces mean faster and more even slaking.
  3. Cover with water, then leave it alone. Do not stir it, do not help it. It collapses on its own, and stirring early just makes lumps that take longer.
  4. Pour off the clear water on top once everything has settled. This removes most of the excess in one step.
  5. Spread it on plaster, two or three inches thick. Plaster pulls water out evenly from below, which no other surface does as well.
  6. Turn it once when the top feels firm, so the underside dries too.
  7. Take it off when it stops sticking and feels like clay. Too soon and it is mud; too late and it is stiff and hard to wedge.
  8. Slam wedge, then spiral wedge, and it is ready.

If you have no plaster

A canvas-covered board, an old bedsheet over a flat surface, or a pillowcase hung up over a bucket all work. They are slower and less even than plaster, and they carry none of the plaster risk, which for some people is the better trade.

The one that matters

Plaster, and why it is the real danger

Everything else on this page is a nuisance. This one destroys work, weeks later, in a way that is impossible to trace back.

How to Make a Plaster Slab for Wedging and Recycling Clay Rachel Hamilton Making the slab properly, which is most of how you avoid the problem in the first place.
  1. What happens. A fragment of plaster in a clay wall absorbs moisture from the air, expands, and pops a crater out of the surface. Sometimes during drying, more often after firing, occasionally months later on a finished pot.
  2. It cannot be fixed or filtered out. Once plaster is in a batch of reclaim, that batch is suspect forever. Most people throw it away, which is the right call.
  3. Old plaster bats are the usual source. Plaster softens with age and use. A chipped edge or a crumbling corner sheds into the clay sitting on it.
  4. So check the bat before you use it. Chips, soft patches, crumbling edges. A bat that is shedding gets retired, not used carefully.
  5. Never scrape plaster with a metal tool. A rib or a scraper on a plaster surface takes plaster with the clay. Wood, plastic, or your hands.
  6. Seal the edges, with tape or a wooden frame, since that is where plaster bats break down first.

If you think plaster got in

Say so and throw the batch out. Nobody will be annoyed, and the alternative is somebody else's piece failing in a kiln for a reason they will never work out. A bag of clay costs a few dollars; the trust in shared reclaim costs more.

The other contamination

Mixing clay bodies

Less dramatic than plaster and far more common. Two clays in one bucket is the usual way communal reclaim goes wrong.

Shrinkage rates differ

Two clays that shrink by different amounts, fused together in one pot, pull against each other as they dry and fire. That shows up as cracks and warping that look like a making fault.

Firing ranges differ

A low-fire body mixed into stoneware and fired to cone 5½ is the serious version. The low-fire portion goes well past its limit, and it bloats or slumps.

Color changes unpredictably

Iron-bearing dark clay mixed with white porcelain gives a mottled gray nobody chose. Glaze then reads differently over it, which is a slow way to lose a color you liked.

Grogged and smooth do not mix well

A heavily grogged body blended into porcelain gives you the worst of each: gritty to throw, and less strong than the grogged clay was.

Small amounts are usually survivable

A little of one stoneware in another of the same firing range is rarely a problem. It is the low-fire into high-fire and the porcelain into everything that cause real trouble.

Which is why buckets are labeled

One bucket per body, labeled, and put your scraps in the right one. That is the entire protocol and it is the difference between usable communal reclaim and a bucket nobody trusts.

The upside nobody mentions

Why reclaim often throws better

Reclaim has a reputation as second-rate clay. In practice a lot of potters prefer it, and there are real reasons why.

  1. Age improves plasticity. Clay that has sat wet develops better working properties. The particles align and bacteria break down organics, which is why aged clay feels smoother and more responsive.
  2. Potters used to do this deliberately. Clay was traditionally aged for months or years before use, and some traditions still do. Your reclaim bucket is an accidental version of the same practice.
  3. It is usually softer. Easier to center, more forgiving to pull, and noticeably kinder to beginners than a stiff fresh bag.
  4. The smell is a sign it is working. That swampy reclaim-bucket smell is bacterial activity, and bacterial activity is what is improving the clay.
  5. The trade-off is consistency. Softer clay slumps sooner on tall forms, and batch-to-batch variation means it is the wrong choice for anything that has to match.
  6. Which suggests a use for each. Reclaim for practice, for learning, for one-off pieces and for anything hand built. Fresh clay for a set, for a commission, or for a form pushing the limits.
The smell

Mold, smell and how long it keeps

  1. Mold in a reclaim bucket is normal and mostly good. It is the organic breakdown that improves plasticity. Old, smelly clay is better clay to throw.
  2. It does not survive the kiln. Everything organic burns out long before the clay matures. There is no trace of it in a fired pot.
  3. It is still worth basic care. Keep the bucket lidded, do not lean over it and inhale, and wash your hands afterward. If you react badly to mold in general, wear gloves and let somebody else wedge the old stuff.
  4. Unfired clay keeps indefinitely as long as it stays wet and covered. There is no expiry date, and a bucket that has sat for a year is usually better than one mixed last week.
  5. Drying out is not a problem either. A bucket that dried to a solid block is not ruined; it is just back at the start of the process. Break it up and slake it again.
  6. The smell can get genuinely unpleasant in a warm room with the lid off. A splash of bleach or vinegar knocks it back if it becomes antisocial, at some cost to the plasticity you were gaining.
At The Clay Hole

How it works here

  1. Scraps go in the right bucket for the body. That one habit is what keeps communal reclaim usable for everybody.
  2. Nothing but clay and water goes in. No plaster, no sponges, no tool handles, no cup lids. Anything that is not clay makes the whole bucket a gamble.
  3. Check a plaster bat before you put clay on it. Chipped or crumbling means retire it, not use it gently.
  4. Never scrape plaster with metal. Wood, plastic or hands.
  5. If you think you contaminated a batch, say so. Nobody will be annoyed. A silent bad batch costs somebody else a piece they cared about.
Read this after a bad batch

What goes wrong

Craters popping out of fired pots

Plaster. A fragment absorbed moisture and expanded. It is the one contamination that cannot be salvaged, and the batch should go.

It never stops being mud

Too much water and a surface that cannot take it away. Plaster pulls water from below and evenly; a plastic tub does not. Spread it thinner, or get it onto plaster.

Lumps that will not blend

The scraps were not dry before they went in the bucket. Damp clay does not slake, it just sits. There is no shortcut back except drying it out and starting again.

It cracks as it dries or fires

Usually two clay bodies with different shrinkage in one pot. Occasionally uneven wedging. Keep bodies separate and slam wedge properly.

Gritty when it should be smooth

Grogged clay got into a smooth body. Not dangerous, just unpleasant to throw and impossible to undo.

Slumping on the wheel

Reclaim is often softer than fresh clay. Let it stiffen a while longer on the plaster before you wedge it, or use it for shorter forms.

Questions we get asked

The ones that come up at the tables

Is reclaimed clay as good as fresh?

Often better to throw, and less consistent. Age improves plasticity, so reclaim tends to feel smoother and more responsive. What it loses is predictability, which makes it the wrong choice for a matching set and a very good choice for practice.

Why do my scraps need to dry out first?

Because dry clay slakes and damp clay does not. Bone dry pieces collapse into slurry within hours of hitting water. Damp lumps sit there for days and then need to be broken up by hand.

Can I mix different clay bodies in reclaim?

Best not to. Different shrinkage rates cause cracking and warping, and a low-fire body mixed into stoneware can bloat or slump when it goes past its range. Small amounts of similar stonewares are usually survivable; porcelain and low-fire are not.

Is the mold in the bucket a health problem?

It smells worse than it is, and it genuinely improves the clay. Keep the bucket lidded, do not put your face over it, and wash your hands. If you react badly to mold generally, wear gloves and skip the oldest buckets.

Why is plaster such a big deal?

Because a fragment in a clay wall absorbs water, expands, and blows a crater out of the pot, often after firing and sometimes months later. It cannot be filtered out or fixed, so a contaminated batch has to be thrown away.

How long can reclaim sit in a bucket?

Indefinitely, if it is covered and wet. Unfired clay does not spoil, and aging improves it. If it dries into a solid block, that is not ruined either; break it up and slake it again.

Do I have to use plaster?

No. Canvas over a board, an old bedsheet, or a pillowcase hung over a bucket all work. They are slower and less even, and they carry none of the plaster risk, which some people consider the better trade.

Is reclaiming actually worth the time?

For your own trimmings, usually yes; they are clean, known and already in front of you. For a large communal slop bucket, that is somebody's job rather than an obligation. Fresh clay is a few dollars a bag, so if the time is scarce, buying clay is a reasonable choice and not a moral failure.

One last thing

Free clay, at the price of your attention

Reclaiming is one of the few things in pottery with no technical difficulty at all. Nothing about it requires skill. It requires you to dry things before wetting them, to keep bodies separate, and to look at a plaster bat before you put clay on it.

What it gives back is a bucket of clay that costs nothing and usually throws better than what you bought. And what it asks in return is that you are careful with the one contaminant that nobody can undo. Keep plaster out, and everything else on this page is just patience.

Dry it, slake it, dry it on plaster, slam wedge it. Free clay, better to throw than fresh, at the cost of your time. Keep bodies separate and keep plaster out.

If you want the honest cost accounting, why reclaim throws better, and the six ways it goes wrong, switch to the Comprehensive Version at the top of the page.