I think you shouldn't remove the rust if you are going to keep it.
Rust actually acts as a protector on the metal. Just wipe it with an oily rag every so often.

If the wooden rims are buckled at all then here is what i do.
Dismantle the spokes completely and then tie the rims as tight as possible to a metal rim that is straight.
Bind the rims with twine all the way around as tight as you can.
Soak them in hot water for a while and then let them dry naturally.
When fully dry they should be straight. Don't try to straighten them with a spoke key how you would a normal rim.

Then the fun starts when you rebuild the wheels. For some reason the spokes turn into spaghetti!