How to get plaster of paris out of a plastic container, and how do you dispose it?
My dad made me use plaster of paris for my papier mache project. I told him that it was a bad Idea, but he wouldn’t listen. It hardened in the container almost as soon as I mixed it. It is stuck to the container, and it’s hard. It also says not to put it down the sink as it will clog the pipes.
It is safe to put the block or chunks in the trash – it is as neutral as concrete. You are not supposed to put the liquid extra down the drain because it will set under water and block the drain if it collects – turn that out on newspaper, wrap it up and put in the trash.
Getting it out if the plastic container will depend on its shape – if it is straight sided or curves in toward the top, you may not be able to get it out except by carefully cutting/chipping at it and you may slip and cut the plastic.