The opening page of the Technology section in the June 7, 2004, issue (18:37) had a short article about using ethylene to ripen coffee beans. The story closed with this: "By application of ethylene to the entire plant, the entire plant will ripen at once, making manual and mechanical harvesting of coffee more productive. Hopefully they'll wash it off before Starbucks gets the beans."
Ethylene is a gas with a boiling point of -104°C. There is no need to wash it off.
John Spevacek, PhD