Hi Meako,
First... If the khukuri in question has a lion head for a buttcap, i wouldnt bother putting this much/type of work into it. It is usually just a wall hanger.
The best way is to finish sand it down with 240grit and work up to about 400 grit.
You may need to use a file to remove deep scratches and such.
Then you are pretty much ready for the buffing wheel. I use the grey rouge, which it think is alum. oxide.
This usually puts a decent gloss on it.
For high shine and gloss i use the green rouge, which i think is chromium oxide.
One should be very, very careful when using a buffing wheel, especially with large knives.
A buffing wheel can yank the knife out of your hands and send it flying before you can utter a syllable of a word...it happens just that fast.
I cannot stress this fact enough....
Always wear eye protection.
If you've never used one before, get someone with experience to show you the subtleties.
Make sure the wheel spins towards you, you will usually be using the underside of the wheel depending on it's size.
This way if you catch the knife in the wheel it will be thrown away from you and not at you.
If you have to use the face on a larger wheel, make sure your feet or any appendages are out of the way of travel of the knife if you should lose control of it.
Never use the wheel in such a way that the knife will be thrown at you. Murphy will take over and you could be impaled.
Always buff with the cutting edge pointing in the same direction as the wheel is spinning. If you buff edge to, it WILL catch and rip it out of your hands. It is only temping fate to do so.
Apply rouge to the wheel and begin buffing lightly for a few minutes. This will warm the rouge and it will cut better. Then apply just enough pressure to polish. To remove any excess rouge, use the light touch again.
If the blade gets too hot, let it cool. It is possible to overbuff and create a skin of annealed metal on the edge.
It is also possible that overheating the blade could affect the temper, although it is nearly impossible to ruin the temper without scorching your hands badly. I never let the blade get so hot that i cannot touch it.
If you have more questions, post them up and we'll try to answer them!
. that would look like crap.