Last winter I rust blued an old Mauser "parts gun" and found it to be an enjoyable project.
I used disposable latex gloves to handle all parts and worked on clean newspaper in between coats. The parts were boiled in de-ionized water which is available at the grocery store. I made a rust box out of scrap plywood, mainly because the garage was somewhat cold and dry. Had I done this project during the hot, humid summer the rusting box would have been unnecessary.
Patience is required. All parts were highly polished and in the white before I started. I did all of my carding with very fine steel wool. Small parts were placed in a wire mesh basket for rusting and boiling.
Here is the result:
