How do I get rid of this rust in the trunk?

ESP47 said
The trunk of this car was covered in POR15. I began removing it and had to do a lot of rust repair to the passenger side of the trunk. The drivers side metal feels solid but I can't seem to get rid of this pitting that was underneath the POR15. The metal is strong so I don't want to go through the process of cutting it out. I've hit it with every type of wire wheel and disc you can imagine and it won't budge. I've also used naval jelly and another rustoleum type rust remover and that won't do it either. Do you guys have any suggestions?

View attachment 1715203522

View attachment 1715203523

The only solution to repair it right is to replace the metal with new stuff.
If it's solid other than the pits, why wouldn't you just reapply the POR 15?
I can't understand why you would go to the bother of removing it and trying to treat it with something else.
This is specifically what it was designed for and it appears to have been doing it's job...........