i was reading into fixing the rust on inside of my doors saw some said to use the por 15 and others said it doesnt work.. anyone have a particular preventer i should use? its starting to move towards the outside.. would like to stop it before it gets worse.

 

i am a big por 15 guy sand it down or grind it down if u can with out going to deep then paint with with por then put a coat of outer paint over it por can not be exposed to any type of sunlight or it comes off... sunlight is the only weakens it has lol