Rusty water damage to emulsioned walls, how do i remove rust

[richardec]

I had a radiator burst overnight in the en-suite and rusty water has run through the floors and down my hall walls. I'm letting it dry out before attempting to re-paint.
Though how do i get rid of the rust marks in the emulsion on the walls and architrave so it doesn't show through the new coats of emulsion when I paint it in a few days?

 

[joe-90]

Why didn't you wipe it off? Overpaint with an oil based undercoat and then your usual finish.

 

[sparkwright]

Try cleaning with a mild detergent.