Celluloid was invented in 1869 in Newark NJ, but wasn't used for chips for quite a while. Bakelite was developed in 1907–1909 by Belgian chemist Dr. Leo Baekeland, and cartalin is a form of bakelite and was developed much later. Seymour says plastic chips began in the late 1930's and most home poker chips were plastic after WW II.

If this message board let people edit their posts, I would have added that poker wasn't "invented" till after Washington died -- early 19th century.

Robt.

.
.
.
Humphrey Bogart and Lizabeth Scott in "Dead Reckoning" (1947), at craps table.
http://www.antiquegamblingchips.com/StillsA_TopMaleStars.htm