Wash your hands!

I am looking for a cute saying or sign to post up at my house for visitors to wash their hands and not kiss on the baby when my sweet angel comes in October. That is the beginning of flu season and prime time for RSV. I watched my little brother go through it and it was the scariest time for my parents, and I want to prevent that. I've looked on Pinterest and there's not that many ideas, but I need one because of the unclean habits my SO's family keeps (including smoking, not bathing often, and wearing dirty clothing). I want to be able to kindly explain that the baby will not be held if certain standards of cleanness can not be met, without stepping on toes or causing issues with my SO.