When it comes to extracting the resin casting from your mold, it is extremely important that you familiarize yourself with the drying and curing time of the specific type of resin you have used. You must wait for the full drying time period to have passed before making any attempt to de-mold your cast. Once the resin has set completely, it should be easy enough to get the casing from the mold. Provided of course, that you applied a non-stick spray or release agent to your mold before casting.