Instructions
Bring your harmonica into a music store with a large selection of harmonicas and accessories. You do not have to open up your harmonica and remove the comb before visiting the store; they should have the tools to do it in a simple fashion. Call ahead to check on the store's stock and knowledge regarding harmonicas.
Ask to see the selection of wooden combs for the harmonica and show the salesperson your harmonica so he knows which ones fit your model. Wooden combs come in many different sizes and are made from several different woods, including light woods like bamboo and hard materials like high-density wood composites. The difference is in the kind of tone the harmonica produces, and is largely a matter of personal preference by experienced players.
Choose the wooden comb that best suites your needs, and have the salesperson or musical technician install it in your harmonica. Test out your new harmonica comb by playing a full scale on the instrument. If the harmonica doesn't sound the way you want or expect, try a different wooden comb. Experiment with the combs until you get the tone and sound you are looking for.