I was given this advice over 10 years ago, when I was pretty new at chip collecting. Anyway, it worked. Here is what the chip looked like before the crayon:

Here it is after the crayon:

The white crayon wipes off really easily, too. Not so sure about pencil.

Not sure how it will work on a dirty white chip, but I would guess you would see it, at least a little better.

Michael Siskin