I've been looking into this Sharpie+mug+350 degrees craft and it looks as though many people have been experiencing fading or the colors coming off altogether. Therefore, I would like to share this blogger's page. She explains to the tee how she cooked her mug at 425 for 30 minutes and then left the mug to cool in the oven. The results: a permanent cup at last! Check this out!
Pinner says...Attention all beginning sewers (or those who have thought about it) "how to sew using a sewing machine" -- This is a SUPER great beginner guide... I just might give sewing a try. Just in case I ever get to.