Here's my summary from the FAQ page at
http://www.tx3.net/~howardw/Khukuris/ConstructionMaint.htm :
Care of knives HW
People use a number of products to keep their khukuris in good shape.
Marine Tuf-Cloth by Sentry solutions - This is easy to apply and effective.
There have been some reports of light rust spotting even after the application of Marine Tuf-Cloth, but
most people do not appear to encounter this problem. Cliff Stamp uses Marine Tuf-Cloth on the blade, then coats with a layer of vegetable oil.
Renaissance Wax is a petroleum-based wax that has a finer crystalline structure than natural waxes. It is clear and PH neutral. It was developed for use in museum collections where it is applied to all sorts of surfaces including photographs, wood, leather, metal and paintings. This wax is fairly expensive. I paid $25 for a small container. The wax will inhibit corrosion on the blade and the blade edge, help preserve the leather, and inhibit corrosion on the brass or silver fittings.
Paste Wax, beeswax, carnuba wax - Natural waxes have many of the advantages of Renaissance Wax, but they may contain acids that will cause deterioration over time. They also may not be clear.
Silicon Oil - My favored solution. The silicon oil will not oxidize (turn rancid) as many organic oils will.
Mineral Oil - Available in any pharmacy, also does not turn rancid.
Vegetable oil Many forumites use olive, canola, peanut, or other vegetable oils. These are readily available and inexpensive. Some users report oxidation and the formation of gummy deposits with certain organic oils.
Nothing You can just not worry about rust. Regular use will keep the worst of the rust off. The blade wont rust through in your lifetime unless youre using it for a saltwater dive knife. Probably not even then.
I find that my khukuris fall into two categories. They are either users or display/weapons. With users, appearance is secondary. The primary concern in care is ease of care and preserving the life of the tool.
For knives in the display/weapon category I want to preserve the smooth bright finish and the sharp edge during long periods of nonuse. I don't mind investing some time in care initially, but I don't want to have to keep returning to the knife to care for it.
In order to preserve the bright finish and sharp edge of display/weapon knives with minimal effort I have arrived at the following process.
1. Sharpen blade to desired state.
2. Wipe blade down with Marine Tuff-Cloth.
3. Let blade dry.
4. Buff off cloudy residue with a cloth.
5. Coat blade, handle, karda, chakma, and sheath with a thin layer of Renaissance Wax.
6. Buff waxed surfaces with cloth.
7. Put blade away until needed.
This treatment will preserve the finish and the sharp edge on a blade that is not in use for some time.
Using blades see frequent use around the house and in the field. They are handy tools but I don't devote a lot of attention to them. They get an initial wipe down with Marine Tuff-Cloth when I first get them. After use I wipe the crud off the blade with a scotch-brite pad, then wipe the blade dry and put it away. This treatment only requires a 20 second stop by the sink on my way into the house. The finish on these using blades quickly becomes a dull gray.
I occasionally treat the wood handles of the users to a rubdown with linseed oil. The horn handles receive rubdowns with lanolin or Hooflex occasionally. If I am going to put one of the users away for some time I may give the blade a protective coat of mineral oil or wax.
Hooflex is a hoof treatment available in feed stores. It is made of pine tar and lanolin. It smells good and shines the horn handles right up.