How do you liquify hardened plaster?

To liquify hardened plaster, you can add water to the plaster and mix it thoroughly. Start by breaking up the hardened pieces into smaller chunks to facilitate mixing. Gradually add water while stirring until you achieve a smooth, pourable consistency. If necessary, you can heat the mixture slightly to help dissolve the plaster, but be cautious not to overheat it, as this can alter its properties.