I have actually removed sharpie from several things. Permanent isn't always permanent. Sharpies are also not as crisp as a Pigma Pen. They tend to "bleed" out a little. I guess you should figure out how long the fabric is expected to last, how much laundering (sharpies really fade over time), what you are trying to make, etc. I figure that if I'm going to the trouble to make something special I want it to last as long as possible.