Whether you plan to expose the quilt to cold or not, the fact that the marks come back means there is a chemical left in your fabric. They were not developed for use on fabric and the long term effect of that chemical residue is not known, as far as I have been able to determine. That alone is enough for me not to use them. They can also leave a ghost image on very light fabric. I have read that if you starch after marking, the marks can also become permanent, and I have heard at least one horror story of them coming back after a quilt was shipped and never completely went away again. I know some people love them, but they are not for me.