You can save money by removing all grease, dirt, and paint yourself. Everything must be disassembled. No bearings, seals, or gaskets can be on the parts.
I plug and mask all holes, threads, and mating surfaces (when needed). Aluminum is very porous and I may need to bake it prior to applying the powder coating to remove any embedded oils.
I will remove the old paint or prepare the surface by media blasting with sand or aluminum oxide, depending on several factors.