“Four cents short of a nickel”

“Four cents short of a nickel” is a description of someone who is “not all there.” The expression is found on many lists of “full deckisms” (that is, “he’s not playing with a full deck”).
 
“Four cents short of a nickel” is cited in print since at least 1987.
 
       
Canonical List of Fulldeckisms
(As in, “He’s not playing with a full deck.”)
A compendium of insults and “not all there” comments from various sources, beginning with rec.humor, April 1987.
(...)
420. Four cents short of a nickel.
 
Short of a Full Deck - Chez Goodman
Four cents short of a nickel.
   
24 November 1987, Mass Media (Boston, MA), pg. 11, col. 1:
Her (Barbra Streisand—ed.) head down, her hair tangled, her face sullen, she does indeed look as if she’s four cents short of a nickel.
   
1 January 1989, Chicago (IL) Tribune, “Politics gives Glendale heights a big-city flavor” by Jody Temkin, Du Page, pg. 1:
“These people all appear to me to be about six cents short of a nickel,” said Sullivan, when asked if she put Fonte and Pastore up to the petition challenge.
     
Google Groups: rec.humor
Newsgroups: rec.humor
From: .(JavaScript must be enabled to view this email address) (Bryan Hannahs)
Date: 7 Mar 91 09:35:49 GMT
Local: Thurs, Mar 7 1991 4:35 am
Subject: Re: Cliches (was Re: Schoolhouse Rock)
 
He’s about 4 cents short of a nickel.
   
Google Groups: rec.humor
Newsgroups: rec.humor
From: .(JavaScript must be enabled to view this email address) (Mick Shatswell)
Date: 6 Aug 91 16:05:36 GMT
Local: Tues, Aug 6 1991 11:05 am
Subject: Re: Not Too Bright ... (PLEASE READ!!!)
 
About four cents short of a nickel.
     
Miami (FL) New Times
Published on May 12, 1993
(...)
Scotti has a sizable voice, but his delivery is all pose, nothing that Rick Astley couldn’t knock off on his way to has-been rehab, and the flat stab at the Harold Melvin and the Blue Notes chestnut “Wake Up Everybody” is about four cents short of a nickel.