SDH-MT is correct about the wood shavings. I have been asked to fix a lot of inletting goofs. Some of them may be filled with epoxy (ugly at best) or have wood inserted and then re-inletted.
The best process is still wood to metal fitting. Use a well matched piece of wood(it is best if you are using a piece of the same wood the stock is made from) and use wood glue as Steve mentioned. Wood glue dries with the least noticable line IF the wood is matched with grain and color.
Epoxy, super-glue, or poly-glue have always shown a glue line, for me. I learned early in my career this looks un-professional and clients do not usually accept it. Some people have said they have good results with "coloring" the epoxy to match the wood. I have used wood dust, coloring tints, different types of wood colors, multiple mixtures of colors, all to some degree of acceptance by the client but not up to the standards of the ACGG professional stockmaker of past or present. I am really good at hiding the repair with colormatching techniques used by furniture repair professionals. It is still not the same thing as making the gap disappear with good inletting techniques.
Now to the specific of your question....all of the above processes will work to fill the gaps. If you are aspiring to make the best quality job, you are going to have to learn the art of making your goofs blend seemlessly. Go slow, be patient, do not hurry, do not get mad at not getting it right the first time. Remember...Thomas Edison tried over 2900 times to make a light bulb. Mr. Edison remarked that he had learned 2900 ways NOT to make a light bulb, not that he had failed 2900 times. Perserverance will pay off and you will be proud of your work when you are done.
Dennis Earl Smith
The Stock Doctor
ACGG Regular Member