Newplast is a non-drying, non-setting modelling material. It is virtually identical to Plasticine, and can be re-used many times. Newplast is sufficiently pliable to make a wide variety of models, but is firm enough to retain its shape indefinitely. Newplast is non-toxic. This product will keep for many years if stored correctly in a refrigerator in cling film. This is the modelling material made famous by Ardman Animation.
Sadly this company has recently gone out of business, so it will only be available while stocks last.