Having a dent in your speaker's dust cap really doesn't affect the sound, but it can factor into the resale value. To remove a dent easily, use pliers to bend a needle into a 45-degree angle, use the needle to puncture the dent, and then turn the needle and gently pull it so that the angled-end raises the dent up. When you're finished, use a felt pen to cover the tiny hole.
Thanks goes to YouTube user GT10gaming for sharing this tip. If you're buying store-model speakers, now you can have confidence that the dust cap dent on the demo unit can be easily repaired, so go negotiate a steep discount.
Repair A Dent On A Speaker's Dust Cap (5 steps/ 5 minutes) [Instructables]