Foundation for string blocks
Here's something I discovered.
I was making some string blocks for a charity recently & was looking for some other type of paper to use for the back (to tear off). My DD is a chiropractor & uses disposable face cradle paper on her table. I got a roll from her recently & tried it & it worked great. It's thin, soft & tears away very easily. If you are in good with a doctor or chiropractor, they may give you a roll (or the end of a roll) every now & then for your string blocks. I bet that paper that doctors use on their exam tables would work great also.