I was given old blocks last summer with discolored fabric. I soaked them in vinegar and water, changing it often, b/c my blocks were DIRTY! Most of the discoloration came out. I had 25 blocks, and the object, in my case was just to clean them up not make them look brand new. Some of the stains didn't come out but these were done by my girlfriends mother. I will eventually give the quilt back to her, once completed, and didn't want to make new blocks. I just needed them a little cleaner.