Clay is a surprisingly durable material when stored correctly — it can last for years without degrading. But improper storage can lead to clay that is too stiff to work, too wet to handle, moldy, or frozen and ruined. Here is everything you need to know about storing clay in a home studio.
Storing Unopened Clay
Unopened bags of clay from the supplier are already wrapped in plastic and will keep for a long time — often a year or more — if stored correctly. The main enemies are extreme temperatures and physical damage to the bag.
- Temperature — keep clay above freezing at all times. Clay that freezes and thaws can become unusable — the ice crystals disrupt the clay structure and cause it to become crumbly and lose plasticity. A garage studio in a cold climate needs insulated clay storage.
- Avoid extreme heat — prolonged exposure to high heat can dry out clay even through the bag. Do not store clay near a kiln or in a space that gets very hot in summer.
- Keep bags intact — even a small hole lets air in and the clay near the opening will dry out. Seal any punctures immediately with tape.
Storing Opened Clay
Once a bag is opened, the clay begins to dry from the exposed surface. To keep it workable:
- Rewrap tightly — fold the bag closed and seal with a bungee cord or tape. Press out as much air as possible before sealing.
- Store in a sealed container — a plastic bin with a lid is ideal for partially used clay. Place a damp cloth or sponge inside the container (not touching the clay directly) to maintain humidity.
- Double bag — for longer storage, place the wrapped clay bag inside a second plastic bag and seal.
How to Rehydrate Clay That Has Gone Too Hard
Even well-stored clay sometimes gets too stiff to work with. There are two approaches depending on how the clay dried out.
Method 1: Bucket Submersion (Unopened or Intact Bag)
This works when the bag has no holes and the clay has dried out uniformly. Fill a 5-gallon bucket halfway with water. Add about half a cup of water directly into the bag of clay, then seal the bag tightly and submerge it in the bucket. The weight of the water pressing against the bag forces moisture through the plastic and gradually into the clay. Leave it for several hours, then check. If it still needs more, add another half cup of water and repeat. This method is slow but requires almost no effort — the water does the work.
Method 2: Slab and Rewrap (Opened or Partially Used Bag)
This is for clay that has been opened, partially used, and left to stiffen — it’s more hands-on but works faster. Open the bag and slice the clay into 1.5–2 inch thick slabs. Lay the slabs out and mist the cut surfaces thoroughly with water from a spray bottle. Stack the misted slabs back together, wrap the whole block tightly in a damp cloth, seal it inside the original bag, and leave for 24–48 hours. The moisture migrates evenly through the slabs and brings the clay back to a workable consistency. If it’s still stiff after 48 hours, repeat the misting and wrapping once more.
- Tip: Slicing the clay exposes more surface area for moisture to absorb into — it’s far faster than trying to rehydrate a solid block through the outside alone. The thinner the slabs, the faster it works.
Storing Work in Progress
Pieces at different stages of construction need different storage conditions:
- Plastic clay and soft leather-hard — cover loosely with plastic sheeting. You want to slow drying, not stop it entirely. Wrapping too tightly can cause condensation that makes surfaces sticky.
- Leather-hard pieces being assembled — use a damp box (a sealed container with a damp sponge) to keep multiple pieces at the same stage of dryness for joining. See our Damp Box guide.
- Pieces waiting to be trimmed — cover lightly with plastic and allow to dry evenly. Rotate pieces that have a tendency to dry unevenly on one side.
Reclaim Clay Storage
Reclaim — trimmings, failed pieces, and dried clay scraps — should be kept wet in a sealed bucket until you are ready to process it. Keep a dedicated reclaim bucket with a lid in the studio. Dry reclaim can be reconstituted by breaking it into small pieces, submerging in water, and allowing to slake down before processing into workable clay.
For more on the reclaim process, see our Clay Reclaim guide.
What to Do with Clay That Has Dried Out
Clay that has stiffened but not fully dried can often be rescued by wrapping it tightly with a damp cloth and leaving it in a sealed bag for 24–48 hours. The moisture migrates back into the clay and it becomes workable again. Fully bone-dry clay needs to be reconstituted through the slaking process — broken up, submerged in water, and dried back to a workable consistency on a plaster drying board.
