Repainting Garage Door

[nick crisp]

Bit of a mundane one, but is it ok to use Nitromors on your typical metal, up-and-over garage door? And what's the best way to repaint after? Obviously after cleaning thoroughly it'll need a primer coat before applying paint, but what's the best way - brush ok? I'll source the right outdoor application paint and primer (gloss white finish to replace the ugly old brown colour that comes off with just a wipe with a wet rag now). Don't have any spray guns and don't want to spend that much now, just prepping the house for sale. Cheers Foccers!