Earlier quoted context omitted.
Just use an alcohol wipe and you're good to go. Cleaned and disinfected, don't know what else would bother you?
Alcohol isn’t sterilizing. E.g. Not very effective against non-enveloped viruses, for example. I’d leave ‘em in the sun personally. But putting it random stuff at the edge of your ear is probably low risk when it comes to activities people do on the regular.
There's also a device which bombards small device like earphones with UV for a couple of minutes. Got it at work. My over ear headphones don't fit, but my Sony in-ear with noise cancelling do. Oh, and they still work afterwards, of course.