Using the LMF browning solution (or other like Wahkon Bay, if you can find it) is no trouble. You just have to get everything degreased very well, and use rubber gloves so as not to leave greasy fingerprints anywhere. When you card the rust, you should use steel wool, fine brass brush, or what I use, a fine wire wheel on a buffer (like a grinder-just be careful with small parts, they have a way of launching!). When carding, you are just removing surface scale, the idea is to leave some rust, not polish down to bare metal. Most people make the mistake of rushing it, especially if the humidty is low, allow more time between carding/appling solution. I will usually get a nice coat by end of a week, carding in the morning and evening (putting solution on after carding). If you get spotty areas, just clean the area with brake/carb cleaner after carding, there may be oil there, sometimes its the metal itself having more properties then the rest, but it should develop rust in time. If you use steel wool to card, clean off the oil on the steel wool using a degreaser or laquer thinner (not mineral spirits) ,you should use a dust mask when carding. When you are done, make up thin paste of baking soda and water to wipe over the metal (this will stop the rusting process), rinse with hot water, wipe dry, oil it. I use boiled linseed oil to seal the surface, let hang for a couple more days. Thats it.
I'm not much for the products where you heat the metal and then apply solution, such as "Plum Brown", it will work better for small parts. BUT, the big concern is the poisons that you can breath in when working with it, arsenic is one of the bad things, use in ventilated area!!!!
Good luck, it's not that had to do.
