Alcohol is pretty much useless as an agent of sterilization. You can
grow nasty little things in it, as the entirety of the medical world
Any store that uses those little alcohol wipes does so out of
well-meaning ignorance, or, they are pulling off a little showmanship
designed to suggest their customers health is protected.
I agree with Peter Rowe. Hands are indeed dirtier than the peirced
ear holes. Unless there is an infection, they pose no more risk with
than clip earrings - both of which are cleaner than the faucet handles
in any public restroom.
Bleach, the best antiseptic, will discolor silver, (I don’t know about
gold) and could do harm to stone colors and epoxies.
So what to do? Relax, and if you must, put them in an ultrasconic
with good amonia, or by hand, with soap and water, sprayed off with a
steamer, or, just forget it. If your customers seem to have an ear
problem, do what you feel is right…