Some people have reported success with using a piece of tape to "pull the dent out", and others have reported success with VERY carefully using a vacuum.

If I were doing the vac thing, I'd make sure it wasn't under full pressure.

FWIW, the dustcaps would not effect the sound, but I can understand that it would bug you!

::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::