Originally Posted by Linda Ohio now GA
For cleaning the clear acrylic blocks, try Purell hand sanitizer. It works great and is cheap.
Purlell is 62% alcohol and alcohol can damage your acrylic blocks.
A couple of years ago I did some research on cleaners for my blocks because several had developed fine spider cracks. I found that because I was using harsh cleaners (the old Stazon cleaner, alcohol, 409, etc) I had ruined my blocks and eventually the spider cracks will all join together and my blocks will break into tiny little pieces.
SU sells a block cleaning cloth and works really well on my newer blocks. It the stains are older you have to rub a bit but it does get them off and my blocks are polished to a nice shine.