I’ve been meaning to write up how to clean dirty AirPods and AirPod cases for over a year. Now 9to5 Mac has done it for me. All the techniques recommended by Michael Potuck are good ones. I’ll just add a few more:
A slightly damp cotton swab is a great way to clean gunk out of the AirPod case rim and rim lid. It’s amazing how much dirt I can clear out with that step alone.
+1 on the Blu Tack. You’ll find so many uses for that stuff.
Make sure to check the lightning charging port. I thought my AirPods died, and it was just lint from my pocket in the charging port.
Related to AirPods Pro, I bought a pair of memory foam replacements for the rubber inserts, and now they work much better with my ears. Your mileage may vary.