Harriet

Hi, I make a lot of molds and usually make them from turned plaster but have a fired ceramic piece I'd like to cast and wanted to see if anyone has any extra tricks or suggestions? I will soft soap the unfired bit at the bottom, the rest has got a gloss glaze on it. I imagine it'll be harder to get out of the mold but could be wrong. Any tips/suggestions would be welcome! Thanks in advance.