Inside of panels - rust converter?

[wasco]

I finally got to do a bit of work on the car recently - just installing the new locks and removing the door panels to put in storage, but I'm wondering what I should do with the inside of the doors and quarters? The inside of the doors had some undercoating, which has released revealing a rusty coating. What is recommended for cleaning this out and sealing the inside of the panels? You can see in the pictures where the car had side body bumpers at one point and the holes were filled, probably with a brazing torch, causing the undercoating to fall off is some areas (not shown). I've used Rust Converter type spray paint in the past - good enough after a cursory cleanup? Also, is the plastic with the criss-cross tape original?
Thanks!

 

[Beekeeper]

por-15 would do excellent

 

[oldbee]

Try this and you'll lube up all the linkage too.Stays kinda like hand cream&it sticks.

 

[gkent]

I had that black paper-like tape in my doors (69 RR)

 

[Beekeeper]

Try this and you'll lube up all the linkage too.Stays kinda like hand cream&it sticks.

View attachment 511527

We use that stuff at work it's great stuff

 

[eldubb440]

por-15 would do excellent

por15 aint good for much, but it does have a place......and this is the place!