I do not understand what this cleaning was done for? To my opinion metal parts from box looks ready for painting without any cleaning works. They needs only in some adjustment works and to smooth out traces of mould junctions.
Can you show me more close what is the parts surface you receive after cleaning. For example like this:
http://img-fotki.yandex.ru/get/9324/..._ae68e872_orig
http://img-fotki.yandex.ru/get/9503/...0_d4ed681_orig