This milk bottle collar label from the Sheffield Farm Dairy shows that the tumblers were filled with cottage cheese. The promotion ran for 10 weeks, starting on February 20. Note that the copyright imprint reads, "© 1939 Walt Disney Productions."
Label images via Hakes.
The first six glasses in the series are marked "© W.D. Ent." while the last four are "© W.D.P." Walt Disney Enterprises was the entity of the company that handled the merchandising in the 1930s. It was consolidated into Walt Disney Productions in 1938. So it's likely those with "W.D. Ent." were designed before this consolidation occurred, and the last four were added to the collection after.
All of the glasses include multiple characters. The first six in the list were also sold as a boxed set in stores. They may still have been used, however, by some dairies as premiums.
- Snow White and the Seven Dwarfs
- Mickey, Minnie, Pluto, and Parrot
- Donald, Donna (Daisy), Huey, Louie, and Dewey
- Big Bad Wolf and Three Little Pigs
- Ferdinand the Bull, Senorita, and Matador
- Ugly Duckling
- Greedy Pig and Colt
- Goofy and Wilbur
- Raccoon,Turtle, Fawn, and Rabbit
- Wally Walrus and Penguins
Mickey, Minnie, Pluto, Parrot (orange with yellow banner).
Donald, Donna, Huey, Louie, and Dewey (red with gray banner).
Big Bad Wolf and Three Little Pigs (green with yellow banner).
Ferdinand the Bull, Senorita, and Matador (maroon with orange banner). Note the glass with its metal cottage cheese lid. It reads, "Belle Vernon 3740 Carnegie Ave. Sealtest 10 oz. net."
Ugly Duckling (green with blue banner).
Greedy Pig and Colt (red with black banner).
Goofy and Wilbur (green with black banner).
Raccoon,Turtle, Fawn, and Rabbit (yellow). Smaller 4.25" version seen here with no banner.
Wally Walrus and Penguins (blue). Smaller 4.25" version seen here with no banner.
As we see in the two glasses above, a shorter series of tumblers was also released, measuring about 4.25" tall. Some of these lacked the title banner while others have been found with it. A comparison between the two styles is seen in Hake's Official Guide to Disney Collectibles, second edition, p.851.