Prepping metal for paint

I recently purchased a brass bed from a thrift store. In examining I noticed rust and also spots where the brass coating has worn off. I am assuming the bed was probably only coated with a brass finish. My question is I would like to redo the bed in a bronze finish, how do I prepare the metal so the paint will adhere?

I would suggest you take fine 00 steel wool ⇦ on eBay or Amazon [affil link] and clean the metal bed parts. All rust should be removed with the steel wool. A once over on the good metal parts with steel wool is also required for a good tack base. Suggest you use a Metal type Gray primer first and spray your finish (two times)Paint Color after the primer is dry.