what Can I do for my fingerboard

Hi everybody,
I have a Nazih Ghadban' s oud, I love it, but I have a buzzing the problem is at the same point indicated by Master Jon Vergara in this video about the Buzzing https://www.youtube.com/watch?v=oPRvng77Hjk.
I've researched the problem, the oud was made in 2006 by Mr Ghadban so I don't think that's a problem of structure.
After having examined the fingerboard, I found 2 littles depressions on it a the same buzzing point who have the same shape as the diameter of the strings I fix it with a piece of transparent tape on the depression.
The problem is that I would like to fix it definitely because it's not very aesthetic and I wouldn't damage the fingerboard. The solution would be to sand the fingerboard ( Expensive ? risk ? ) ?
I use actually a Pyramids Orange set with the 3rd Strings in silver.
Is the Nylon better for the fingerboard and the buzzing ?
I have to change my strings because they are rust, which set do you advise me for a 3rd in nylon and what type of chemical produit for clean the fingerboard ? ( I'm very satisfied of Pyramids ... but If Nylon is better I can change ).
thank you for your answers and I apologize for my approximate english

Quote: Originally posted by Dr. Oud

You can fill the depressions with JB Weld epoxy, a glass filled epoxy that cures very hard. You'll need to scrape it flat with a single edge razor blade after it sets (4-6 hours), but before it cures all the way{8 hours}. If it does cure you'll need silicon carbide sandpaper to sand it flat. Use a flat sanding block as long or longer than the entire fingerboard to avoid making a cup which will buzz as well. A wood fingerboard can be sealed and hardened with tung oil. apply liberally, let dry an hour then wipe off the excess.