From October 13, 1929 Brooklyn Daily Eagle:

“Topeka, Kan. — Rules for the guidance of kissers were issued today by the Kansas Board of Health in co-operation with the United States Public Health Service. 

Never kiss in crowded places or in a poorly ventilated room, the instructions say, but if you must kiss, take a hot mustard foot bath and avoid drafts as precautions against colds.

Other rules:

Guard against sudden changes in temperature when kissing. Kissing in a coonskin coat one minute and lighter apparel the next is extremely dangerous.

Don’t kiss any person who has chills and fever.

At a party where postoffice and similar games are played, be sure to gargle frequently.”