Older, 58mm keychain-sized Victorinox Swiss Army knives (and a few modern ones) have a nail file witha rounded "nail cleaner" tip instead of a screwdriver. The tip of this nail file is slightly rounded, so it works extremely well for cleaning under your nails.
Uses: The nail file has a roughened metal surface which works quite well for taking rough spots off fingernails or toenails. The tool is hard enough that it probably won't ever wear out.