With oil based clay scales, you don't need a release since the oil basically does the job. If you use fiberglass, you might want to apply a few layers of acrylic spray to seal the moisture.
Here's a video tutorial for foam scales:
For clay scales, you can purchase a clay/pasta machine and a cookie cutter of your desired shape. All you do is apply pieces of clay in the machine so that it's flattened out, and then you punch out clay circles with your cookie cutter. Here is an image:
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