Once washed with detergent the marks won't come back even if put in the freezer, at least on the quilts I've used it on. Too many quilters have tried the experiment of not washing, freezing, washing freezing, starch the fabric first, not starch. The marking color is non toxic and archival quality. I use them for all markings and haven't had a problem that bothers me about them but most quilting mistakes don't bother me, so test first.
Last edited by BellaBoo; 02-25-2013 at 11:20 AM.