As you can't clean the mic capsule itself, or any integral pop-shield…
One 'mickey mouse nose' foam pop shield per user, which can be sanitised afterwards. Alcohol wipes for the mic body, between users.
Or, the cheap & cheerful, if not great sonically - a thin baggie over the whole thing, inverted & discarded after each use.
Might be better to leave the 58 at home for this & use the 57 with pop shields/baggies.
As per Shoeps - Microphone use & Covid-19
Violawave designed a UV box to sanitise mics inside 5 minutes - might be OK if you have two mics - How do you sanitise your microphones against Covid-19?
Shure have detailed info on cleaning specific mic types - How Should I Clean My Microphone?
Oooh, late find - Mic "condoms" - disposable fabric covers, eg Amazon US link
…and, of course, hand gel on the side of the stage, for use on the way on & on the way off.