That's quite an agricultural approach to nib removal is it not?.
Personally, I have never yet come across a kit nib that cannot be removed from its housing with finger pressure alone, without even the need to warm it up first. I would also always remove the housing from the section first, to eliminate the possibility of damaging the section, which with the exception of the cheap Chinese Jr Gent, simply unscrews. (The Chinese seem to feel the need to glue the housing into the section on the cheap Jr Gent, but a good blast with a hairdryer first weakens the glue.)
But as Dan has said, if you've unscrewed the housing from the section, you can buy the new nib pre-assembled, so you don't need to remove the actual nib in any case. You just buy the nib in a "kit compatible" housing, screw the old one out and screw the new one in.
Now where can you buy those I wonder?