This type of clay is often used, in conjunction with a filleting ball, to create a temporary smooth radius on the inside corners of patterns before taking a mould off the pattern. The clay is reusable and resins don't stick to it.
POLYMER MODELLING CLAY AIR DRY POLYMER MODELLING CLAY 10kg
DAS 1 Kg Air Drying Modelling Clay Self Hardening Modelling Sculpting Clay - UK
DAS 1 kg Air Drying Modelling Clay Self Hardening Modelling Sculpting Clay - UK
BOHS White Air Dry Modelling Clay 1.36kg Squishy Soft Clay for Arts Crafts Sculp
Air Dry Clay, 26 Colors Modelling Clay, 8 Tools, Booklet, Crafting Kits for Kids