How to store polymer clay

Storing polymer clay is a big topic, considering the prices of better brands and mediocre quality of worse or no-brand stuff.

PC may be stored in different conditions, depending on its state (phase of use).

1. Raw unprocessed PC

2. Raw PC rolled into millefiori canes/formed into parts of the final piece

3. Raw finished objects (things covered in millefiori, raw beads)

4. Baked stuff

So, in order:

1. Raw unprocessed PC

First thing is, raw PC dries. It is affected by air (gets hard/brittle and dry, forces you to use lots of energy to revitalize it), temperature (it gets pre-baked and there is no way to undo this) and various unfriendly substances (it reacts, loses colour or dissolves).

Unfriendly substance may be, among others, water. Water will make a muddy mess out of your PC and it’s hard to clean this up afterwards – I’ve never had that much patience. I won’t even go into solvents and related – just keep your PC as far from the chemicals as possible.

Other unfriendly substance for polymer clay is… any other polymer clay. Of course if they made contact in an uncontrolled way. That’s because depending on colour and brand, this may lead to them sticking together, contaminating or even mixing the colours, if you don’t manage to separate them cleanly. It’s prudent to keep your pc separated into colours, preferably each in a different container.

Some brands of clay have a defect that demonstrates as “bleeding” colours. No idea if it’s the dye or the plasticizer, but at least once I handled black clay which not only was not black, but purple (after mixing with white gave various shades of pink), but black-white millefiori after a while became black-pink. Look:


Chemistry also affects what you can store your clay in. As polymer clay is, simply, PVC with plasticizer, when in contact with other plastics of similar nature it may damage it. And in damaging it, its own structure will change (as plasticizer is used up to dissolve the other material), so it’s good to know which materials to avoid. If you unwrapped your clay, you can:

* try to wrap it back in the original wrapping and together with other pieces in a common storage, making sure they don’t touch (meaning that the clay doesn’t touch)

* each piece into an individual ziplock baggie – clay doesn’t react with that easily

Boxes and other equipment, like swirling aids, should be:

* glass

* polipropylene (they have “pp” in a triangle somewhere)


* bottles and jars marked “PET” – when exposed to clay, they dissolve as you watch them

* hard cd/dvd cases – they may seem great ie. to swirl, but they get awful dirty immediately – thats polistyrene, just like ice cream containers (that’s why you should not store clay in ice cream boxes)

2. Raw clay, processed

To store millefiori canes, you can:

1. Cut the cane in equal pieces

2. Take a roll of silicone-covered baking paper and cut piece at least as wide as the cane pieces are long

3. Wrap each piece into that paper tape: wrap one tightly, put the second, wrap around that one and first again, add third and so on, making sure no two cane pieces touch.

4. Put into non-reacting box (best to match length in pt 1 to that box) and put them in such a way that you see the “faces” of canes through the top or, if box is transparent, through the side.

5. All this, with a lid, put into your fridge or, even better, freezer. The canes will be much easier to slice after freezing.

To store elements (pieces of a doll or a box) – flat parts it’s best to layer with baking paper, the more round ones – on something that will not allow them to roll away (VVV of paper, pieces in the “rows”). Remember not to store them for too long, because if they dry, you won’t be able to attach them to the main item.

3. Items covered with clay, beads etc before baking

After covering or finally preparing for baking, we don’t always have enough items to justify heating up the oven (or we plan to create bigger batch of something). Until then, we need to secure them somehow.

It is good to make sure they aren’t exposed to sunlight (colours, chemical structure), water (see pt 1) and dust, which will get stuck to any sticky surface and is hard to remove if the finishing doesn’t include polishing (ie. dolls). From my experience, I recommend lining a baking tray with silicone paper, putting your waiting items there (with appropriate spacing) and… putting them into the oven, if nobody else is using it. Dry, not too warm (yet), no dust and no younger siblings will put their tiny dirty fingers in.

Do not put the items too closely together, as vases or figurines stuck together are hard to pull apart, and sometimes tiny movement of the tray when putting into the oven is enough to move the pieces of clay and get them stuck together.

4. Baked items

Baked polymer clay is effectively plastic. Sometimes crumbly or breakable, but plastic. Heating it up to the baking temperature (130-140 C) doesn’t hurt it, but it shouldn’t be exposed to open fire. Prolonged sunlight exposure can cause colours loss or change, depending on the clay brand.

Clay is easily breakable, so baked items shouldn’t be kept in places where they can be crushed, chipped or can fall.

Baked/cooked clay theoretically should not bleed colour, however due to specifics of some dyes and unknown quality of products of some brands, in case of adding clay elements to clothes or covers, and the need to wash these, it’s best to make an experiment of washing a few beads or buttons in warm soapy water with a sample of the cloth.

Sum up: Pay attention how you store your PC in all its various forms, and you will be able to use it much longer than if you leave it unattended. Nothing more wasteful than creating a bunch of interesting items and letting them get covered with thick layer of dust. I know something about it – been there, done that.