How to soften old hard polymer clay. Renew and condition kato, premo, sculpy and fimo clays.

How to Soften Old Hard Polymer Clay

Can it Really be Saved?

Ever dug out your polymer clay in excitement, only to find it as hard as a rock? Don’t despair and chuck it! With a bit of work and patience, you can soften that old hard polymer clay and make it like new again. I recently renewed all of my old polymer clay which I originally purchased 12 YEARS AGO while creating artworks for the Children’s Ward of the new Geraldton Regional Hospital. I’m gearing up for some serious sculpting!

Firstly, if your clay is all mixed up sort it into clean colour groups or dare to mix some together and create new shades of your own. Take a sharp blade (tissue blade, scalpel, or Stanley) and carefully chop your clay into very small pieces. I did one colour at a time to minimise cross contamination. You could also use a blender to chop it up quickly (if you have one specifically for art purposes).

Empty each batch of chopped clay into individual snap lock bags and add some drops of Mineral Oil (Baby Oil) or some Kato Liquid Polyclay. Only add a small amount to start with and give it a good shake and a massage to coat all of the pieces thoroughly.

Now walk away and leave your bags of clay for at least a day to begin rehydrating. Give them a check and a squeeze every so often to see if more oil or Polyclay is needed. Continue to gradually add as necessary over time. Once your clay begins to soften, start to bring it back together by beating and rolling it with an acrylic roller. You can even minimise handling by initially rolling it while still in the bag – a good method to keep your white clay clean.

To finish, finally put your renewed clay through a pasta machine several times and smooth any small remaining lumps or inconsistencies. Store between sheets of wax paper and seal tightly in an air tight container. Keep your renewed polymer clay in a cool place and next time you reach for it – it will be perfect and ready to go. Happy sculpting!

Additional Tips

  • If you get impatient (as I did with the yellow) and add to much oil, your clay will become to soft and sticky – don’t panic. Work the clay on a cardboard surface to absorb the excess, or place it between sheets of paper and under a weight to leach it out overnight.
  • Keep baby wipes nearby to keep your hands clean throughout the process.
  • Sculpy Mold Maker also doubles as a clay conditioner and works well to soften polymer, I find adding a touch beneficial when using the pasta machine if clay remains a bit rigid.
  • Sculpy Clay Softener also hydrates dry crumbling clay, though I don’t have any personal experience with this product as of yet.
  • If you have a very large amount of clay, Mineral Oil would be the most economical choice.

I’ve got Potential in the Bag

After hearing of my clay-saving efforts and OCD colour sorting excitement, my lovely friend and talented polymer clay artist Debbie Crothers gifted me a huge bag of old clay to renew! Challenge accepted and underway…


Rachel Weaver

Rachel Weaver

Freelance Creative at studio 8T4
Rachel Weaver is a Freelance Artist, Designer and Photographer who creates in a wide variety of media. Her work often exploring the quirky and macabre with an emphasis on dramatic light and shadow. Blending the lines between the reality of our natural world and the realm of fantasy, Rachel loves to bring unusual creatures to life. An eternal passion for horror creeps quietly into her pieces, combined with a wild imagination and a generous touch of personality.

Rachel continues to actively and passionately participate in a range of exhibitions, prizes, collaborations and community projects. She resides in her hometown of Geraldton, Western Australia with her partner, two dogs, two cats and carnivorous plant collection.
Rachel Weaver

Leave a Reply

2 Comments on "How to Soften Old Hard Polymer Clay"

newest oldest most voted
Notify of
Bonnie Thorpe

Very inspiring! ! Looks like beautiful products in your imagination! Gotta’ get my creative juices flowing! Thank you for posting!