Gel ink pens are absolutely permanent. My husband left the cap off and dropped it on one of his dress shirts, where it wicked into the fabric for some time before it was discovered. I tried EVERYTHING to get that stain out. I even replicated the stains; put several blotches on scrap fabric and experimented with everything the internet recommended, from laundry products to brake cleaner. Nothing worked. I finally gave up when I came across a law enforcement website that recommends people write checks with gel ink pens, because criminals can't bleach the ink out of the paper.