Kathy, Pour the water off the top of the plaster, then stick a thick
roll of newspaper into the plaster. The newsprint will work like a
wick to draw remaining water out of the investment, leaving it
semi-solid. If you remove the roll of newspaper and let it dry
another day of two, you can knock it all out of the bucket and easily
dispose of it. I use heavy 3 mil contractor trash bags to dispose of
the semi-solid investment from there.