I do these things so you don’t have to experiment on yourself……
11,000 rpm 4 inch grinder (without the safety guard, of course…because I’m a guy) with an 80 grit flap disc…
skin on knuckle
0.0000004 seconds of contact time.
Skin gone.
But it is clean and should heal rapidly.
YMMV.
Now you know, just in case you were wondering.
Owie…
Pressure washer catches side of thumb this weekend while blasting the underside of a mower deck. Thumb is about an inch from the nozzle. Same time lapse. Same result. Probably cleaner than yours though…