Rust in tunnel under passenger seat

[Eminent]

Hello. I found some rust in de tunnel under the passanger seat (see the red area in the picture).
I think the liitle hose from the airco-system is the cause from this, it was hanging inside the car instead of outside.
The airco never worked since i buyed the car last year, but i think it did by the PO's.
My question. Is it safe to cut off the top of the tunnel so it would easier to work on?
After that i would like to weld it back on, ofcourse.
Anybody who had the same problem?
If so, what did you do to solve this problem.
Tips are welcome.
Thanks.
Regards Rini.

[Larry & Norma]

Has the rust rotted the metal or is it just surface rust under flaky paint. I waited for mine to dry out in the garage and then squirted dinitrol
(waxoil type) into the access holes. That should slow any corrosion down. After all its lasted 40 years so far!

[Eminent]

Thanks for your answer.
It's not rotted, but indeed rust at the surface.
Paint is not there anymore, so i think it's worse than in your case.
I allready bought a can of Dinitrol, but i just wanna be sure that i don't have to dive under the seat again in a few months or so because it didn't work out.
40 years is a long time indeed.
The W108 drove to '99 in California. After that it came to the Netherlands where it's a sea climate.
Hope that doesn't affect if i go for Dinitrol.
Thanks.