[eric2011 (OP)]

Hi

What homemade release agent prevent POP casting to stick into concrete mold? What household chemicals can do this task? pop is plaster of paris

[Colin2B]

I would suggest you seal the porous surface of the cement eg pva glue/sealer and then use thin layer of washing up liquid.

[Petrochemicals]

Smooth the surface so the pop does not sink deeply into the texture. Make a cement grout for the outer layer. Or use nothing but fine sand in your concrete extremley well smoothed.