My grandmother used to paint her quarters with red nail-polish (not certain if the color was significant or if that was merely what she wore and therefore had available). From talking with my mother, the understanding is that Grandmother did this to distinguish those coins in her coin purse that she would later need to feed to the laundry machines in her apartment building. Why she went through the trouble of doing this and carrying them with her everywhere instead of simply setting them aside I do not know. At any rate, these coins would make it into circulation in the region of Oakland California where she lived most of her life, and once I remember her having gotten such a coin as change for some purchase, causing her to remark that it was a sign that her money was making its way back to her, thus serving as an omen of better financial times for her ahead.
A few years ago I found such a coin, but failed to hold onto it. I think I will sort through my change jar later and see if I still have it.