when I cut out pieces for different blocks or multiples of the same to replicate a given block several times, I store the pieces in a "baggie" and lable the "baggie" with a permanent marker. When I am finished with the project, I take the baggies, clean the permanent (not really permanent) sharpie from the baggie with rubbing alcohol and I am ready to reuse them. I was amazed to find out how many different things alcohol will remove permanent sharpie from!!