This is a tip that I think will work.
Most of us are having our workplace now cleaned regularly for example, the front counter in many shops is wiped every hour.
Why not make a sign in the window of what you are doing with a picture like this.
Our front counter because of COVID-19 is being cleaned and disinfected every hour. Deep cleans are done every XXX etc. If you are using, for example, a hospital-grade disinfectant, why not put it up too?
It you have a hand sanitizer for the public use, why not make it a hand hygiene stations with a poster?.
If you have an email newsletter, why not show a photo of you doing it with a brief note?
Show them that you have a good hygiene program!