Well, it sounds like those stain erasers are surprisingly high tech! I've used them--there's some kind of abrasive component, but it's very fine (and quite possibly, it isn't hard enough to dig into most surfaces). Though, I'd still be careful about using them on metal and acrylic, just in case...
Well I tried the stain eraser and still did not get all of the deposits off. I got tired of the futility of it, so I cleaned it up, picked the best side for the front and applied the acrylic vinyl background to the other side. Hopefully it won't be too noticable when filled.
