How do I prep a 2 drawer metal filing cabinet to paint it?

Give it a light sanding, make sure it's clean, and paint it with rustoleum or tremclad in your choice of color, tremclad can be applied by brush/roller, or you can buy it in the spray form.

First you need to clean it well. Sand it a little so that the paint can adhere. Rustoleum makes great spray paint for metal in a lot of colors and even textures and metallics. Have fun!

Wash it with warm soapy water first. I would lightly and roughly sand it a bit then wipe off the dust with a damp sponge. Spray it over cardboard or something you can toss away after.

What other Hometalkers did.

https://www.hometalk.com/search/posts?filter=paint%20file%20cabinet#inline

Just sand lightly with a very fine sandpaper, then clean with a slightly moist cloth and tape off any areas you do not want painted. Spraying is likely the easiest and quickest way to paint. Be sure it is paint for metal! Many great new colors to pick from, so choose one you love. Spray goes everywhere so cover items in your garage you don't want to have a faint "mist" of spray on in the future. :) Have fun! Here's some additional ideas...http://makeityours.co.uk/how-to-guide/make-metal-filing-cabinet-fabulous/