Hi Steve,
If you have some antique khukuris, don't try to make them look too new, as it will lessen their collectors value. Only do what is necessary to preserve them, and put them in "using" condition. (my opinion only)
For newer pieces...
Brass and horn can be buffed with a cotton wheel on a bench grinder, or even chucked in an electric drill. The red rouge polishing compound that comes with the buffing wheels is good for brass and horn. You apply the red rouge to the running buffing wheel, then buff the work. Reapply frequently. DANGER The buffer is the most dangerous power tool in the shop, so be careful. Nothing like a 3600 rpm buffer grabbing a razor sharp knife and throwing it at 60 miles per hour.
When buffing horn, use light pressure and don't stay in one spot too long, as it can burn. If it has deep scratches, you can use 400, then 600 grit sandpaper first.
The carved wood handles are cleaned with a toothbrush and mineral spirits (paint thinner). After drying for a day, I use a toothbrush again to work some Tung Oil, or Tru-Oil Gunstock finish, or Watco Danish Oil finish, into the carved handle. A couple of coats is usually sufficient.
For smooth wood handles that I want to really shine, I use the following process. Good luck and have fun!
Steve Ferguson
First, use 2-3 layers of masking tape to cover the sharp edge of the knife for safety.
1. Use mineral spirits or paint thinner and a toothbrush to remove the red rouge polishing compound if necessary, and wrap masking tape around the bolster to protect it from scratches.
2. Start sanding with 220 grit sandpaper. When down to bare wood, move to 320 grit, then 400, 600 grit, always sanding with the grain. I use a hacksaw blade with the "set" of the teeth ground off the sides to clean out the grooves.
3. Apply a heavy coat of Tru-Oil with your finger. You can even sand the wet Tru-Oil with 600 grit sandpaper to make a slurry of wood and finish to help fill the grain. Smooth it off with your finger.
4. After 2 days wipe off any that is still tacky, and let it dry 1 more day.
5. Lightly sand with 1000 grit wet or dry sandpaper. Wet the sandpaper in a bowl of water. It makes the finish very smooth, and keeps the paper from loading up. You don't want to remove finish, just dull it. You can reuse this piece of sandpaper until you complete one handle.
6. Dry off the handle thoroughly and recoat with a VERY THIN coat of Tru-Oil.
7. The following night, if the finish is dry, wet-sand, dry it off, and recoat with a THIN coat of Tru-Oil. Repeat every night until the pores are filled, and you can look deep into the finish and see the soul of the handle. This will be from 10-20 coats.
No stain is used.
Chandan and Rosewood are very oily woods. I have had problems with the Tru-Oil staying tacky for many days. If this happens, after each coat I heat the handle with a hair dryer for 2 or 3 minutes to set the finish. It seems to harden the finish before the woods natural oils can leach into it.
I'm not recommending these methods, just reporting what I've done. As always, your mileage may vary.
Thanks to Walosi and Yvsa for their input and past posts regarding refinishing handles!
