Idea's to keep frame from rotting inside out?

[aggressive male]

I think I have the rot on the outside of my frame under control but I know inside the boxed sections it's not looking too good. Someone told me I can stop the rot by spraying grease all inside it but what a mess that would be at the frame openings. I was thinking maybe somehow block off all the openings and fill the frame rails with grease? Anyone have some idea's for me? What do you think is the right grease to use?
I need something that won't hurt rubber because the body mounts are inside the frame.

[Satatic]

Jeez substitue grease for something like rustoleum. I notice that on my grease gun some kind of oil is always spreading out from the nozel and dripping on the floor and that just a little bit I could only imagine what a frame full would be doing.

[aggressive male]

Jeez substitue grease for something like rustoleum. I notice that on my grease gun some kind of oil is always spreading out from the nozel and dripping on the floor and that just a little bit I could only imagine what a frame full would be doing. I hear you, that's why I'm hoping someone here can recomend something solid enough that it won't leak out of the cracks like that. Or destroy the body mounts.

[TonyL]

I think you can buy frame wax. A bodyshop supply company should have it. We spray it into frame horns and stuff. Someone help me out, what's it really called?

[1969CamaroRS]

When I had my frame powder coated it got a pretty good amount inside the frame, you might consider something along those lines, or some sort of rustproof dip. Rather than grease which could cause some grief trying to track down fluid leaks in the car.

[TonyL]

I remember now. It's called "cavity wax" most auto body paint shops carry it. The gun you need to apply it is cheap. Little 1/8" long skinny pipe with a fan nozzle on the end. You stick it into the frame cavity and spray as you draw it back out, coating the inside of the frame rail with wax.

An article on it. (http://www.fordscorpio.co.uk/cavitywax.htm)
what it looks like (http://www.chemicar.com/tekton_cavity.php)

https://static1.pt-content.com/images/pt/2008/02/cavitywax-1.jpg
https://static1.pt-content.com/images/pt/2008/02/undercoatgun-1.jpg
https://static1.pt-content.com/images/pt/2008/02/bs_rustproofing-1.jpg

[aggressive male]

Hey thanks Tony!

If this stuff works anything like that 1st article says it does it seems like just the miracle I need if I want to continue driving what I've got. I guess according to that first article I'll have to wait til it's hot to put it on. A little messy but it sure would be way easier to deal with the mess it makes than it is to deal with rust wouldn't it? Anyone here use this stuff?