I dug out a mold my Dad made for a stepping stone. It is not silcone, but a low temperature rubber type. It is sitting in a plaster cast to hold it's shape and it is stuck in it, slightly askew. I may have to just try it the way it is and see how it comes out. When I try to carefully pry the mold off of the plaster, it is really stuck, especially around the edges. I really want to try to preserve it, as it is a momento from my Dad, who just passed. Any ideas on how to get it out? I just trying wetting it around the edges. I think this afternoon I will just try to pour it "as is" because I am afraid I am going to ruin it. Does anyone have any tips on peeling it out from the plaster? If it does not come out good, positioned as it is, should I crack the plaster from below and try to wash it away. I'd really like to preserve it. If the one I pour today, using cement and mold release, comes out OK, what material would you recommend for making a new mold?