thanks for putting your thinking caps on for me. sometimes when we work too hard, we aren't thinking like we should. of course, i have heard about the wood shelfing turning antique quilts, and soo...... duh, for sure, since cardboard is made out of wood, it would turn our fabric after a while also. meaning...old scrap cardboard like i was using all last nite, and this morning..... so i willl gradually transfur it to 'acid free' stuff. THANKS FOR SAVING MY STASH FOR ME... i have learned sooo much from this board. want to make the 'house' blocks and just wanted to be able to see what i had.