I use them and wash the quilt afterward. There have been many experiments where the fabric is washed, starched, not washed, starched, washed not starched, not washed not starched, do all over again using steam, no steam. Results were different when fabric was placed in cold. I don't care enough if the marks come back or not, I figure after several washing they will disappear. Of course no show quilts involved. How excited do we get now when we find an old quilt with pencil marks showing?