“Can you please pull your mask to cover your nose? Thanks!” Is usually how I do it while I’m at work. Customer service voice and all. I’ve also been pulled over by a cop not wearing a mask since COVID started (I was speeding, separate story) and I nicely asked him if I could pull a bit more into the shoulder so we could talk through the opposite side window because my mom’s immunocompromised. I basically just turned on the super nice and went from there, granted I sadly don’t know if this would work for everyone in these situations, but hopefully, this is a good starting point
Well, the 3 main places you typically contract a sickness, is from your nose, mouth, and eyes. You could just walk up to than with your mask over your eyes, and when they ask what you’re doing just say “Mines just as effective as yours.” There isn’t one. They either know and are doing it on purpose in which case they will take it as a challenge, or they don’t know and they’re literally that dumb in which case telling them is pointing out just how dumb they are. Nobody accidentally lets their mask slip like that.