Anti - corrosion for internal of RHS chassis members?

[stew]

Whats the general consensus?

I was thinking either injecting something like waxoyl into the chassis once finished.

Or expanding foam?

Or is it worth bothering?

I was thinking to avoid any rattles etc from inside the chassis.

What do the likes of caterham/westfield etc do?

Im maybe overthinking, but its a sat night and im stuck in! lol

cheers,