Paint and Finishing questions - Obi Wan ANH

So - I have a nice shiny grenade (brass neck to come) and a stark white resin booster section (I epoxied a piece of vacuum pipe to one side that slides snugly into my handwheel.)

What is the best way to finish a machined grenade - chemicals, paint..?

And what about resin pieces - what good paint will get that used metal look? aka not gloss black hahaha ...this is a good question for any resin piece that doesn't need to look shiny actually

Thanks for any insight!