Also if you need an alternative, you could look into a 2 part epoxy putty. I thought it was similar to apoxy sculpt, but i'm thinking maybe not after the comments.
I've used it to resculpt stuff on anime figurines.
I was also under the impression that these were the same thing, just Brand Name vs. generic... Mine is a 2-part, and seems to work well with plastics (no leeching, discoloring, etc., even after years in storage).
Ah, I see.
I know all of the epoxy putties have their own properties and quirks. I've never used apoxy sculpt, though I've always been curious about it.
I personally like tamiya epoxy putty. It is easier to work with then polymer clays for some reason (for me).