Use a pair of fingernail clippers to snip them off . You may still be able to feel a little jagged edge protruding If so slide a board up inside the hide to give yourself a surface to strike against and give each of the snipped off nipples a good sound smack with a smooth face hammer and you wont be able to feel them at all anymore the hammer blow makes flush with the leather and smooth.
I will use the inversion technique next chance i get ,i think its a great idea but if the hide is dry this works

I am not able to trap cats here yet in this part of the state but like the tip on how to handle them when I can .

i swear every beaver i do lately i tell "its lucky i'm not Tracy Truman or he'd turn your nipples inside out.

Hahahahahaha!!!!

Ttt