|I used one of the dual color blue/purple marking pens-- not sure which end I used now -- in marking a neckline binding into fourths. I did press it so that may have been the problem. Anyway, I sprayed the marks with a laundry treatment and washed the shirt. I just assumed the marks were gone and tossed it in the dryer. When I took it out, I saw brown marks where the colored ones had been. As it was white, first I tried a tiny dab of chlorine bleach. No change. I was out of hydrogen peroxide, but I saw some whitening mouthwash (major company) on the counter and gave it a try as it does have hydrogen peroxide in it. The mark was gone in seconds and it didn't damage the fabric. I assume it was the peroxide in it, but it might have been another ingredient that was responsible. Worked for me this time, but can't guarantee it for you or even if it will work again for me. Now, that is my first tip.