I am a teacher and I use this to mark my classroom set of calculators, netbooks, really anything I don't want my students to have an easy time nicking. Once I've engraved, I put correction fluid over it, then wipe it away. The correction fluid sinks down into the engraving marks to make it more visible. Students will take off stickers, wipe off sharpie, but they have yet to find a way to "erase" this method of marking things. A+