I always seem to have these shallow scratches in my thumb, index and middle finger tips that fill with dirt/soot and become so stained that not even 10 minutes scrubbing with soap meant to get dried paint off your hands will clean them. Just have to wait for the skin to fall off. I think most of these are from cheeseholing where the drill bit always has thin pieces of metal 6 in. to a foot long spinning very, very fast.
a team mate cut his finger because he forgot to lock a tape measure. it wasnt a big cut but it took a while to stop bleeding...
Boy are we lucky our sponsors keep a very well stocked first aid kit. I swear, everything from burn gel to antiseptic wipes are in there.
-Vivek