the mom will probably not come back to care for them
To mark things permanently.
No, The mark is on the shell.
A permanent marker is a typical writing tool to mark labels on optical media.
Put some iso propyl alcohol on soft cloth and rub the mark with it.
if it is on the housing (plastic / non screen part) get the aeresol version of "goof off" be sure to use it in a very very well ventilated area ----------------------------------------------------------------- To remove a permanent marker mark of an lcd screen (what i did); dab a little hand sanitizer on a napkin then rub the affected area. This has been proven by me, this will not ruin your screen.
I don't know if this will work on piano keys, but dry erase markers erase permanent marker on white boards. Write over the mark, then erase the dry erase. If the dry erase doesn't come off the piano keys easily, use alcohol.
This is how a store clerk explained it to me when I asked the same question: They "mark" the bills with a special marker to determine if the the bill is counterfeit. If the bill is legit, the marker does not put a mark on it, but if it is counterfeit, the marker will leave a streak.
You mark it with a marker.
Get some nail varnish remover on a cloth and start rubbing then keep repeating this step till all the mark is gone then get a wet cloth and remove the excess. Rub marks left from the nail varnish remover and now the permanent marker should be gone 0v0 \__/
you put a marker called a diploma marker.
The word marker has two syllables. Mark-er.
A circle marker is a symbol on a regulatory marker that is used to mark a no wake or idle speed area.