The last time I went to Annapolis Quilts for Kids I picked up two gallon bags of strings. These leftover bits are often just thrown away. My goal was to make them into something useful.
I grabbed my 6.5" paper foundation squares cut from an old phone book (to me all phone books are old because I never use them any more except for foundation paper piecing string blocks) and got stitching.
I still have plenty of strings left over and I have a pretty good stack of blocks trimmed and ready to have the paper removed. These are perfect mindless sewing. So easy to stitch up and you don't have to worry about perfections. The precision comes when you trim them to 6.5" by 6.5" blocks.