At times I dislike my Laptop. I have started this reply like 2 times now..... Maybe 3rd time will be the Charm...
First off, A little bit of help with Pictures would be great.......
Second there are a few factors in restore repair and I don't know how much is needed to be told here so I will just say all that is in my mind and with any luck it will help you out some....
First I am not an Expert nor do I do Pro Restorations.
Depending on how bad the pipe is and how much you want to take down the finish that is already on the pipe. If you go down to the Naked Brair is going to depend on how deep the stain was on there to begin with. May want to go as far as 150 grit to get to wood if needed. Then go up to 320, 400, 600, 1000 and finish with 1500. Once your done or you think your done check your sanding job with a jewelers loupe or something to check the fine grain. Once you are happy with sanding then you can Stain it if you want to, Or you can keep it natural as some people do. Take the trip buff and wax. There is another part you can do after wax but that is up to you and some just stay with the wax at the end. It will dull over time an will need to be touched up.
If you are going to stain it?! there are a couple different type Water and Alcohol based. if you use water based just make sure that it is dry before you start sanding. IF you are going to use 2 colors, I think the Alcohol based is faster as you can burn it off to dry. Sand and may need to buff some to help even out the stain some. Sanding between 1000 and 1500grit staining for pulling out the briars grain.
I don't know but is said if using water based it can pull out the grains and may make a deep color. Some use both water and Alcohol stains on the same pipe depending on the pipe grain and the results your looking for.....
Once you get your stain where you want it and final sanding then buff with White diamond and Wax.
Just remember while working around the stem area not to sand off to much of the briar.
I am not an Expert or claim to be one. Just some info to help aid in your hobby.
Maybe there will be others that are pro or have been doing them longer then I have to give some Advice better then mine.
Good Luck I would love to see pictures of your pipe before and after...
Thank you
James