It seems to be about the only way to communicate laser settings with any degree of reliability. I've recommended it on another forum as well without comment.
Maybe we could have a pop-up on the new site.
Mike Null
Dist. of Lazer Cutting Grid
www.stl-laser.com
Actually, I have had a similar residue on LaserLights (Rowmark, I believe), but I haven't yet tried the eraser on that product. Haven't used it since I bought those erasers! But I will try it just to see what's what.