I was recently fortunate enough to find some Sanford Penit in those cute little jars The covers say they were originally ten cents apiece...the 50s, maybe? Anyway, they're NOS, so I decided to try them out. The Cardinal Red, Green, Brown, Dubonnet, and Blue Black all work fantastic, and the colors seem accurate to the examples I've found. The Violet, however, was completely seperated--like water and sand, practically. My question is, do some colors just naturally hold up better over the course of time? Or is it totally random? I want to eventually try all the different Sanford inks (I live in a town called Sanford ), but I'm wondering if some of the colors will be harder to find in a useable state than others...