“Diner: There’s a button in my salad. Waiter: It must have come off while the salad was dressing.”

A restaurant joke is:
 
Diner: Waiter, there’s a button in my salad.
Waiter: It must have come off while the salad was dressing.
 
The oldest form of the joke was printed in the Anthony (KS) Republican on February 23, 1923, and this item was soon credited by other newspapers:
 
“A local man found a button in his salad whereupon he wittily remarked that it probably dropped off while the salad was dressing.”
 
     
22 February 1923, Anthony (KS) Republican, pg. 8, col. 1:
A local man found a button in his salad whereupon he wittily remarked that it probably dropped off while the salad was dressing.
       
22 March 1923, Council Grove (KS) Republican “Kansas Comment,” pg. 5, col. 1:
An Anthony man is reported by the Republican to have found a button in his salad and with great presence of mind, remarked: “I suppose it dropped off while the salad was dressing.”
 
12 August 1926, Bellingham (WA) Herald, pg. 6, col. 7:
A Bellingham man who is reported to have found a button in his salad with great presence of mind remarked: “I suppose it dropped off while the salad was dressing.”
 
Google Books
25 January 1930, Friends Intelligencer, “Fun,” pg. 62, col. 3:
Little Marvin found a button in his salad. He remarked : “I suppose it fell off while the salad was dressing.”
 
6 March 1930, Boston (MA) Globe, pg. 6, col. 3:
Price of Modesty
Little Marvin found a button in his salad.
 
He remarked: “I suppose it fell off while the salad was dressing.”—Christian Register.
     
12 November 1931, Philadelphia (PA) Tribune, pg. 5, col. 8:
Little Johnny, permitted to stay up and have dinner with his family who were entertaining guests, found a button in his pear salad:—“Oh mamma, look! I found a button in my salad. I guess it fell off while the salad was dressing.”
   
18 September 1961, Austin (TX) Statesman, “Fun Time—The Chuckle Box” by A. Leokum, pg. 18, col. 5:
Little Marvin found a button in his salad and remarked, “I suppose it fall off while the salad was dressing.”
   
Google Books
Laughs, Hoots & Giggles
By Joseph Rosenbloom
Illustrated by Joyce Behr and Sanford Hoffman
New York, NY: Sterling Publishing Company
1984
Pg. 267:
Customer: Waiter, there is a button in my salad. I want to see the manager!
Waiter: Don’t get so excited. It probably fell off while the salad was dressing.
 
Twitter
Dannie_Lizette9
@Dannie_Lizette9
Customer: Waiter, there’s a button in my salad. Waiter: It must have come off while the salad was dressing.
9:15 PM - 3 Oct 2009
     
YouTube
Ok, here is the joke. Customer: Waiter, there’s a button in my…
botcaster inc. bot
Published on Jan 22, 2016
Customer: Waiter, there’s a button in my salad.
Waiter: It must have come off while the salad was dressing.
 
Reddit—Jokes
Customer: Waiter, theres a button in my salad…
submitted February 10, 2016 by Imsofakingwetoded
Waiter: It must have come off while the salad was dressing.
 
Twitter
lorraine Jo King
@LahLahBean
#mondaymirth
Customer:
Waiter, there’s a button in my salad.
Waiter:
It must have come off while the salad was dressing.
2:25 AM - 4 Jun 2018