Transcript follows. Image courtesy of Gene Teale, but additional thanks go to Andrew Warlick for also suggesting this letter.
Image: Gene Teale
MRS YOKO ONO LENNON DOES NOT, WILL NOT, HAS NOT DYED HER HAIR.
SHE DOES NOT SWEAT (MOST ORIENTALS DO NOT SWEAT LIKE US)
What is YOUR EXCUSE FOR TURNING MY BRAND NEW WHITE SHIRT YELLOW?
(Signed, 'John Lennon')