We sell a good number of replacement Bakelite parts, but it just isn’t economical for us to produce everything.
When replacement isn’t an option, you can try to restore the Bakelite part. Here is a good tutorial on an old Bakelite radio.
In short, clean the piece, rub it thoroughly with 1000 grit steel wood, and then polish with Brasso. I’ve also heard that Simichrome polish works well and might have a little bit of chemical reaction with the Bakelite that helps the restoration.