I got two of these, in about the same condition (worn and dirty) and decided to clean one and see if it improved. Oh boy, was that a mistake.

I'll admit the better one isn't a great prize, except it's old and not that common. But look at the chip on the right and see what happened.

I'm still trying to figure out how to (dirty word comming here) restore the chip on the right.

Just in case, it's a Crumley Hotels crossed branding irons, Elko Nevada, Roulette.

If the image doesn't show what I'm trying to point out. The dirt in the lettering makes the left chip readable, the right one is clean and looks almost like a blank.