I have used WD-40 for number removal with no appearant problems, but
the comment about it's content concerned me. I check the contents on a
can and it contains flammable petroleum distillates. Although mineral
oil is also listed as a petroleum distillate (in some compounds such as
baby oil) it is non-flammable, and might be a better choice - safer and
less irritating - if it works. Haven't tride it.