Over time these levers have developed a rattling sound. It appears to come from the lever rattling against its housing at the pivot point. Intuitively I would tighten the pivot bolt, but it appears to be a rivet, so I can't really do anything with it.
Things I've looked into
The answer to this related question mentions using an o-ring, but because of the rivet-like pivot I can't disassemble the lever.
The sound can be damped easily by just resting my fingers on the levers, but I sometimes prefer to just hold the bar without my fingers on the lever.
Can I silence these rattling levers? Or is there perhaps a compatible lever that does not rattle?