Magic Tricks

Oh..@fermunder...since you posted this in the public forum, my reference to the 'most popular' tab is in the PRIVATE forum for this effect...not here in this public venue ;-)
For reference, in the private forum, there's a whole bunch of other info that is good to know that you won't find here publicly.

Don't use lighter fluid...'nuf' said.
Alcohol is OK if you don't have a dry erase cleaner.
But, once clean, you may want to consider using an additional protective layer of acrylic tape since the back of the box is already a bit 'shiny'. Don't just use/assume that any acrylic tape will work...no, no!
They are not created equally...some won't even 'erase' with a dry erase pen.
Check out the 'most popular' tab for over a years worth of Q & A info that will prove invaluable. This was discussed extensively there.

Lighter fluid is too harsh. Try Gonzo or Goof Off. (Gonzo is my preferred stain remover, but is harder to find than Goof Off.)

I use the backside of the gimmick in my routine since I only use the gimmick and two duplicates that I created an original so It can't look too shiny for me on the back