Adhesive vinyl overlays - C47 & WP43 (DM42), WP3xS, DB48X, newRPL variants available!

[Eric Rechlin]

The Sharpie wipes off without a trace if you use isopropyl alcohol again to clean it, so you are not harming the calculator permanently.

However, some 30b calculators (a small percentage, well under 5% I'm sure) have the blue legends printed on with an alcohol-soluble ink, so the alcohol will wipe the blue key legends off too. But 95%+ of the time this won't be a concern. I've long wondered why some were like that -- I am pretty sure they were towards the end of the production run, maybe even at the end.