*from rabbitgeek notes june 2006*
I use "cold galvanizing" spray paint for cleaning up rusty cages.
You can get this spray at Ace Hardware and other stores.
It leaves a coating of zinc on the metal to fight rust.
I use a propane torch first to burn off the fur/wool. Do not let the wire turn red from heat as this will weaken the wire. Burn fur/wool off before washing or will have clumps of wet fur on the wire that is hard to burn off.
I wash the cages really well with a hose, a power washer works good. Wet cage down then wait to soak for a few minutes then start washing. Use a brass wire brush or barbecue cleaning brush to knock off the rust and any dried on waste. Let dry.
Spray with the cold galvanizing spray. Be sure to cover bottom and sides of the wire. Let dry overnight.
There will be a little residue that comes off at first but other wise the paint stays on wire for a year and will need some touch up.
If the wire is seriously corroded paint is not going to help, you need to replace the wire.
Have a good day!