I've been using Rem-oil for years, but my new favorite for both cleaning and protection is "Barricade", made by Birchwood & Casey.

http://www.birchwoodcasey.com/news/9588.html

I've been surprised at what one can get away with by storing things in a low-humidity environment. I keep the humidity low in my house (asthma) and store my collection in the upper floor. I've had unprotected pieces sitting around for years and years without any oil or wax, and they only require occassional cleaning as light stains appear. On the other hand, I once forgot a sword in my basement for a few days without the dehumidifer on and it was already covered in rust pits when I noticed it. Similarly, I had trouble with a helm I was keeping in my work office in the basement floor until my office moved to the main floor of the building.

If there's one moral to this story - don't keep stuff in your basement if you can avoid it!

I once did a long term test of mild steel nails protected with a number of products. I left them hammered into a wood block and exposed to the elements in my backyard which is about 500m from the Pacific ocean. Break-free fell about in the middle of the group. Boeshield, the spray-on protectant designed for aeronautical and marine applications, did slightly better. What did the best, by far, is Remington Universal Grease. Now, agreed, this is a rather extreme case and with reasonably careful storage and occasional application, most any decent oil, such as Break-free, RemOil or any good motor oil, will probably do the job. At the end of three months, all the nails were rusted to one degree or another. Rust never sleeps.

My father in law, who is a master machinist and long time barrel fitter for benchrest shooters, swears by Johnson's Paste Wax. Cheap, easy to find, easily applied and, according to him, very effective. He does live in a rather dry climate, but some of his "in the white" items have been exposed to the weather during use with no ill effect.

I keep my bayonets and short swords in boxes with a bag of silica gel. In this case mineral oil works well, but in humid conditions offers little or no protection.