Best Way to Stop Door Rust?

[HyperV6]

I had to remove my door panel to replace my power window motor. Along the bottom seam of the door I can see rust and some rust at the back/bottom end inside of the door. The car was undercoated many years ago. So, there is some undercoat in the doors. The door drains are not clogged. What is the best way to treat the rust inside of the door? I've been looking at POR-15 and Eastwoods Rust Encapsolator. But, I was thinking maybe some other product needs to be put on the rust to try to remove it or stop it like Eastwood's Fast Etch or rust converter and then coating it with POR-15 or Rust Encapsolator. Has anyone come up with a good way to stop the rust that is inside the door? Any suggestions would be greatly appeciated.

Thank you, Craig

 

[Junior Samples]

The bad thing is with rust is that Rust never sleeps, really the only way to stop it is to remove it but encapsolating it does help and that one product thats out there...isnt it like grey or brown going on then it turns black?

IM finding some gumbo staring along my rear fender wells which is an easy fix compared to your problem.

Sucks living in the rust belt

Mike