Stop in for a cup of coffee

I bought a better looking ashtray and receiver this week, and got it yesterday. The metal part didn't need much work had dirt, grime, and cig stain. I took and wet sanded it using medium corse paper and concentrated simple green. A little elbow grease and it cleaned up.
I'd send it to you, but buddy is painting my dash and parts later this week.
Do you dip the parts when you zinc them or apply the zinc with heat??
I haven't a clue to the process.