Well here will be part of your Sharpie School info (as i am now a guru). I personally use Industrial Strength Sharpies for many reasons... they are resistant to water, most chemicals, UV, and can withstand up to 500 degrees of heat. I also paint cars for a living so i can tell you that only the Industrial type can be cleared over and i've done tests to determine the process since it's a common question. Also, Industrial ink is a strager black then regular sharpies as opposed to a purpley black that will fade a little easier. When you look at Industrial Sharpies it says 'Super Permanent ink' in the marker. The only draw back is it's only available in black. You can also use the Sharpie Paint Markers... and thats another world... but if your interested im pretty sure i know everything there is to kno about Sharpies!