Well I use egg crate ceiling tile. Lay out about 12 of them and have at
it, Same ones for painting. When the holes start to get full just empty.
You might be able to get them free from some office building . They look
like crap when a corner is broken off , up in the ceiling , so
maintenance usually just replace them and throw out the old ones. Guess
companies should not complain if you take them. Company would not have
to pay to get rid of them, Also save some space in the landfill. Course
you can always buy new,