Friction creates heat so the marks have to have friction to go away. Tumbling in a hot dryer will work.
I use them. The gel washes out just like any other marking pens you use. I washed a sample after ironing and the marks did not re appear in the cold freezer. The sample I did not wash the marks came back. I trust them more then I trust the disappearing marking pens or the blue wash out pen which can be set permanently with heat. And I don't care if my quilts don't last for generations. They can make their own. LOL
Last edited by Onebyone; 05-23-2015 at 05:57 AM.