Ed,

It is hard to explain unless you have one. I use multi mat to hold down 1.5" aluminum disks when burnishing. After prolonged usage paint coating from disks gets all over mat and it needs to be cleaned. I run tap water on it to get rid of dirt, and dry it with hair drier, back in production.
One drawback with multi mat is that it leaves oily residue on table top and if plates need tape on them for attaching the tape should be applied before placing them on mat.

Tony