sorting sreface rust on chassis?

[baz-r]

as the complex shape of the chassis and the facy im gettig a small amount of serface rust from degreaseing the tubes for welding im thinking of some form of wounder fix as i dont fancy spending hours cleaning it up
we used Phosphoric acid based cleaners where i used to work it lifted off light rusting and made a paint over protective coating its what most rust remidys are made of
http://en.wikipedia.org/wiki/Phosphoric_acid
just a shame i dont know where i can get hold of some

deb janitol altrans is the only thing i can come up with it is a acid cleaner version

whats your solution to the problem