Hello!
I have some BBC Microcomputer cases to restore for a friend. The problem we're having is that they have security ink back from the 80's when it would have been in schools. As you will be able to see in the link below, this is a mark for Shelford School, Nottinghamshire.
Higher res image here but image attached to this post.
I know that, by design, these aren't to come off, but I like to think there is a solution to (pretty much) every problem. This appears to be a rather sticky problem.
Through my googling, I've not been able to really find out what this stuff is. This is obviously by design (or through my poor searching skills), but I think that if I knew what it was then I might be able to find something to break it down or let it go into solution.
I have tried a number of solvents to even make the ink bleed - none of which have even touched the plastic of the ink.
If anyone is able to shed any light on this, that would be great as I think it would be really cool to solve this (if it hasn't already been done so).
Thanks a lot, Luke.