This just in from Are Myklebust:

[On page 42 in John Grant’s book “Encyclopedia of Walt Disney’s Animated Characters” there is a still from the film “Mickey’s Delayed Date” (1947), where the author asks; “Can you decode the posters  behind?”

The pencil drawing for the same background, which can be found at the “Cowan Collection”:

http://cowancollectionanimation.blogspot.com/2008/11/mickeys-delayed-date-1947-pencil.html

gives some answers, since most words here are spelled backward, but not everything is explained in the blog posting.

After studying the pencil drawing, I “cracked” it.

The “decoded” text on the middle poster is:

TUES NITE (= Tuesday night)

PRIZES

FUN

GIANT

JITTER BUG  (= Jitterbug, the swing dance)

CONTEST!

«Orsayday and his Orchestra», on the poster far right, is a spoof of “Tommy Dorsey and his Orchestra”, a popular big band in America at that time.

“Orsayday” is «Dorsay» («Dorsey») in pig latin.]