Pilot FriXion Ball Erasable Gel Pens allow you to erase and rewrite repeatedly without damaging paper or fabric. The thermo-sensitive gel ink formula disappears with the erasing friction of a rubber tip on the end of the pen on paper, or with heat (from an iron or blow dryer) on fabric. Erasing leaves no residue or debris, but it is always best to test your fabric before marking a project - faint white residue can be removed with water after ironing. Mark darts and notches on fabric, highlight sizes and make notes on pattern instructions, trace embroidery projects, mark quilting patterns, and so much more! The gel rollerball ink delivers smooth writing on most fabric surfaces, but for felt or fabrics with a nap, try FriXion Erasable Markers. Pink ink marks well on darker fabrics, just allow a few seconds to dry for the ink to appear. All pens are not recommended for projects exposed to extreme temperatures.