I wish you had posted a photo since it would really help with resolving your problem. The first thing is to make a plan with what you want to do with these blocks. Sometimes blocks are framed and distributed to family members who want to have a part of this relative. If they are simple appliques of Sue, could then they be removed carefully from the old muslin and then appliqued to a new square of muslin?? That is what I would most likely do. I would certainly make sure that you are buying the BEST quality of muslin that money can buy. No one in my immediate family ever did any quilting but a distance Great Aunt first exposed me to quilting. You are lucky to have these precious blocks. Good Luck !!