Re: Shinken Rust Problem
Oh, also, proper oil is a must. With inexpensive shinken I have *zero* problem using something like breakfree CLP. I hate the smell of the stuff, but it is good stuff. On antiques and well done blades I stick with medical grade light (and I mean really light) mineral oil. Or simply buy a bottle of so-called choji oil (super light grade mineral oil with a drop of clove for that lovely smell). If you're using it correctly a single small bottle of sword oil (Bugei sells the stuff from Japan as do a couple other places) should last years on a single sword. You might want to buy a bigger one if you have a bunch or are always cutting.
Another thing is cleaning the blade. Uchiko is fine and traditional, but you can also hold the sword tip pointed down and gently cover the blade with an ammonia based window cleaner (windex). Use a clean cloth clean the sword as if you're cleaning a window (wipe off the streaks). Then oil. Hold it point down so the windex doesn't seep under the habaki.
You can also use high percentage alcohol (91% or greater) to clean blades. The stuff strips the daylights out of the old oil so be sure to reoil right away.
Really it's not brain surgery. Too much oil is a waste and damaging to the saya and possibly the blade. You only need the thinnest of coatings (it simply blocks the air from the surface of the steel -- oxidation requires oxygen). So keep the blade scrupulously clean, keep your skin oil off the blade (stop touching the damned blade), and keep the surface protected with a sheen of oil.