How to Soften Polymer Clay

At the moment, crafters everywhere are diving into their stashes of craft supplies in order to find more craft projects to keep themselves entertained, and I am no different.

Yesterday, I decided to break out my polymer clay stash in order to make a project that has been on my to-do list for some time, a ballerina.

Excited to get started, I selected my colors, pulled out the clay I needed, and set to work. Almost immediately, I ran into a problem; my clay was rock solid. Every time I tried to work it; it would crumble into lots of little pieces.

Polymer clay is one of the best clays for sculpting, but like any clay can harden if left too unattended for too long.

Fortunately for me (and, as you’re reading this, you!) I know a few techniques for how to soften polymer clay after many years of trial and error. In this article, I walk you through what I know.

Is Your Clay Firm or Old?

Now, all clay should have some form of firmness to it, the firmer to clay the better it will hold all the little details you want to add to your projects. But clay that feels rock-solid and crumbles to the touch is not what we are looking for.

The first thing to figure out is whether your clay has simply become firm because it is cold or whether, if it’s been left unused for a few months, it’s become old.

Figuring out which you’re dealing with is important; firm clay generally needs energy in the form of heat, or my favorite method, giving it a good bash! Old clay is clay that has lost some of its plasticizers, and the only way to make it usable again is to re-add them.

The Squish Test

If, (like me), most of your clay has been left sitting in your crafty stash for months on end, waiting for you to get round to starting all those projects on your to-do list, then there’s a very good chance it will have gotten old.

But here’s an easy way for you to tell for sure, it’s called the ‘squish’ test. It’s not the most elegant of ceramic techniques but it does the job.

Here’s how: pick up your clay and give it a squeeze. Simple, right!

Even the firmer brands of polymer clay should squash slightly if they are fresh, even if they are cold. You should find that you can round off the corners and edges of your block with minimal effort.

If the block doesn’t give way or it crumbles apart, then either the clay isn’t fresh, or it’s partially cured.

How to Revive Firm Clay

Use a Mallet or Neverknead Tool

using a mallet to revive firm clay

Softening firm clay up can be done by rolling and manipulating it with your hands. However, this can take forever and can make your hands get pretty sore, so I don’t recommend it if you’ve got a large project.

Here’s where having some simple gadgets come in handy.

The first choice for me is a mallet. It’s the simplest and cheapest tool to use. Plus, you’ve probably already got one lying around from that time you attempted camping.

Just put your clay in a bag and bash it until it starts to soften. You can even revive old, crumbly polymer clay in this method if it’s not too far gone. As a bonus, it’s great for stress relief!

A NeverKnead tool is similar to a mallet and does pretty much the same thing but it’s been specifically designed for conditioning polymer clay (it can be quite pricey though).

It requires very little effort to use, which makes it a brilliant tool for those with arthritis or weak hands.

Mix with Other Clay

If your clay still feels too firm, you can try to mix it with a softer clay. I tend to mix my firmer Sculpy clay in with my Fimo soft.

This method isn’t always recommended, but I’ve yet to have any problems.

Mixing firm and soft clays can go both ways too, if you’re finding you have the opposite problem and your clay is so sticky that you’re struggling to get it off your fingers, mixing a firmer brand of clay in can help.

Most brands of clay have a long lifespan, indeed some of my clay is a couple of years old and I can still use it with very few problems.

Eventually, however, all clay will begin to lose its plasticizers and will become hard and immovable, and impossible to work with.

All is not lost though!

How to Revive Old Clay

Give it a Bash in a Bag

The only way to bring it back to life is to re-add any plasticizers that have been lost. The first thing to do is warm up the clay.

Firstly, place the clay in a bag and give it a good bash, this will reactivate any of the plasticizers still left in the clay to begin working again.

Next, we start re-adding plasticizers, this can be done manually by ‘kneading’ it into the clay, but it can be hard work and can make your hands sore. Especially if you have a large project to do.

Use a Food Processor

A far easier (and quicker) way to get this done is to use an old food processor. Just crumble the clay in and add the plasticizers bit by bit until your clay becomes malleable again.

Mixing with Other Substances

There are quite a few different types of plasticizers that can be re-added to your clay.

The best, and probably most recommended option would be some translucent liquid polymer clay.

It’s super easy to add to your clay and the results are easy to control, just add a couple of drops at a time until your clay reaches the desired consistency.

I always like to use Sculpey or Fimo brands where possible as I’ve worked with them the most, but there are plenty of other great ones out there.

You can also use other plasticizers, such as mineral oil, Sculpey clay softener or (my usual choice) baby oil. They all work well, but can be unpredictable, make sure you add very slowly, or you’ll end up with a splodgy mess of clay.

You could also try mixing translucent clay in with your project, as with the liquid clay, it produces consistent, easily controlled results, but bear in mind, it will make your clay appear more translucent.

If none of these methods are working for you, it may be that your clay has ‘cured’.

This can happen if your clay has been exposed to high temperatures for a long period of time. If your clay is cured there’s not much that can be done to bring it back to workable condition.

How to Keep your Clay Fresh and Workable?

Buy Quality

In order to try and avoid old, dried out polymer clay, make sure to buy your clay from somewhere with a high clay turnover.

There are plenty of shops and warehouses where clay has been left lying around on a shelf for months before some poor soul buys them.

Before I make my choice to buy any clay, I always give it a quick ‘squish’ test through the packaging just to check.

When you get your clay home, make sure to store it far away from direct sunlight and heat. The heat from the sun can cure your clay, so it’s always best to make sure you’ve got a dark, shaded area to store your stash.

Obviously, this is trickier online, so always go with the best you can afford and you’ll hopefully receive something worth working with.


Once you’ve opened your clay make sure to pop it in a sealed Ziploc bag to prevent the clay from drying out.

Some Ziploc bags can react with the clay, so test it first, by taking a small piece of your clay and lying it on top of your bag, if the bag becomes cloudy where the clay has been, it’s reacting with the clay.

If it stays clear, you’re good to use it.

Ordering Times

One useful tip to know is when (in the year) it is best to order clay if you’re buying online.

Clay can cure in the back of a hot truck so it’s always best to order during the cooler months, Spring and Autumn are generally the best times to buy.

Finally, you should avoid keeping your clay blocks for too long.

It’s better to buy smaller quantities of clay more regularly than to buy a huge stash and not use it for months at a time (like me). But if you do, at least you’ve now got some handy tips ready for how to soften your clay up again!!


I hope you’ve enjoyed this guide to softening polymer clay. There’s nothing worse than getting all excited about a new project only to find the clay you were planning on using is harder than a brick.

Hopefully, after reading and digesting what I’ve written here, all is not lost.