I used my mold with epoxy resin purchased with this company. Very easy to unmould and shinny pieces. I tried it with Vaseline has a mold release but that particular piece came out cloudy. No need for mould release. The only down side is that you can see the fine marks of the plastic in the finish piece. You can only see them in direct sunlight and looking closely but they are there. I will try to do a thin top coat of resin to see if they disappear.

I used epoxy resin in this mould, but the resin just will not come out at all. I also used the same resin mixture for an ice cube mould which worked much better as it was malleable and not hard. The ice cube mould also allowed my resin to cure faster and was cheaper. :-/ ****RESPONSE FROM METAL CLAY LTD: Sorry to hear you were having these troubles. Unfortunately you haven't left your name so we can't get in touch to help you. We always recommend to undertake a small patch test when using new resin or mould, simply mix a tiny amount of resin and leave to cure on the back of the mould. This way you can be sure that the resin releases, and if it doesn't you haven't ruined your mould. It might also be worth me mentioning that all the resins we sell release perfectly from these moulds. ****