A great
19th century marketing
gimmick, the Heinz
pickle pin was the
brainchild of Henry J. Heinz, founder of the Heinz
ketchup-manufacturing empire. Heinz was known for his many
tasteful advertising schemes, including a 40-foot-tall
electric pickle sign in New York City and a pier in
Atlantic City with a 70-foot pickle "perched heroically on the end" (according to
Cecil Adams).
For the 1893 Chicago Columbian Exposition, Heinz had tiny lapel pins made up in the shape of pickles to give out to people attending the fair. Supposedly, the company gave away over a million pins, and Heinz's fortune was made.
Heinz, Inc. still makes the pickle pins, and you can write to them at
Heinz Pickle Pin
P.O. Box 57
Pittsburgh, PA 15230
and they will send you one for free.
sources:
www.straightdope.com
www.asktherick.com (I can't vouch for the accuracy of this site, but it seems reasonable)