Many shooters don't realize that most modern primers are sealed against moisture, or even minor amounts of oil. The advice many of us grew up with, or heard from older handloaders, was to keep our fingers scrupulously clean of natural oil, in order to avoid "contaminating" primers when touching them, making them go bad. But it's been quite a while since water or a little oil has affected modern primers. Yet I still know several handloaders who, despite knowing this, wash their hands before a handloading session, to "degrease" them and prevent duds--just as I still know many guys who change the oil in their vehicles every 2000-3000 miles, because that's what they were taught back when motor oils weren't nearly as good as they are today.
