Somehow I managed to shred the silicone cushion of the earbud on my bike radio. As nearly as I can tell, it got caught between the seat and the back; the missing part certainly isn’t inside my ear.
Anyhow, I have a bag of spare cushions from all the other earbuds, so this isn’t a showstopper.
The adhesive snot holding the earwax filter in place also failed, so I figured I should fix that while I had the hood up. The old filter was all ooky with earwax & oil & dried sweat, which meant that any new adhesive wouldn’t stick. I chopped a disk from a random foam earbud cover with a 7/32-inch hollow punch and glued it in place with some acrylic sealant.
While I had the sealant out, I replaced the tape sealing the vent hole (on the other end of the earbud) with a dot of glop, much as I should have done originally.