Coughs and sneezes spread diseases. Trap the germs in your handkerchief.

-Anonymous
  British Government health slogan, quoted in  J Darracott and B Loftus Second World War Posters (1972).

[Travel] preservesmy young noblemanfromsurfeiting of hisparents,andweanshimfroma dangerousfondness of his mother. It teacheth him wholesome hardship† Whereas the country gentleman that never travelled, can scarce go to London without making his will, at least without wetting his handkerchief.

-Lassels, Richard
c.1650  The Voyage of Italy, or a Compleat Journey through Italy (published1670).

You are offered a piece of bread and butter that feels like a damp handkerchiefand sometimes, when cucumber is added to it, like a wet one.

-MacKenzie, Sir (Edward Montague) Compton
  Vestal Fire, bk.1, ch.3.