Two things that came out of working on a piece:
Had a pin that would not budge; no rust, just being in place for, oh, roughly 80 years. So I mixed up a variation of the acetone & ATF penetrating oil: I used mineral spirits(no acetone, and I thought the ATF would dissolve into the ms better*). Half-filled a jar, put the piece in, capped it and left it overnight. Today, it came out.
Second thing, if you're not aware, if you've got a stubborn pin that doesn't want to move, use a punch with the shortest pin possible. Couple of years back I mentioned making a set with replaceable tips; took the appropriate size and cut it to about 1/4" to break this loose. A shorter tip both flexes less- delivering more energy to the pin- and is less likely to bend.
*Son had tried the acetone/ATF mix, said it worked well, but they tended to separate if it sat for a while. I'd wondered if mineral spirits would work as well, and seems to; and the ATF doesn't separate.