"eighty-six"="nix"

     [This is a fast-access FAQ excerpt.]
This verb meaning "to eject or debar from premises, to reject or
abandon" was previously an expression used by waiters and bartenders
indicating that the supply of an item was exhausted or that a
customer was not to be served.  Morris Dictionary of Word and Phrase
Origins says:  "[...] 86 may well have come from a number code
created by [...] soda fountain clerks [...].  Originally, according
to the American Thesaurus of Slang, it was a password used between
clerks to indicate:  'We're all out of the item ordered.'  The
transition from this meaning [...] to the bartender's sense of
'Serve no more because of the shape he's in' is fairly obvious.  The
number code developed by soda clerks was very extensive [...].  A
hissed '98' from one soda-popper to another indicated 'The assistant
manager is prowling around.  Watch out.' [...]   And most cheerful
warning of all, 87 1/2, meaning 'There's a good-looking girl out
front!'"
   The earliest clear citation is from the February 1936 issue of
American Speech, which gives the definition "Eighty-six, item on
the menu not on hand."  The Random House Historical Dictionary of
American Slang cites a comedy with a date range 1926-35 in which a
waiter gives his number as 86.
   AHD3 gives the etymology:  "Perhaps after Chumley's bar and
restaurant at 86 Bedford Street in Greenwich Village, New York
City."  But most other dictionaries, including MWCD10, suggest that
eighty-six was rhyming slang for "nix".  On its AOL message Board,
Merriam-Webster Editorial Department writes:  "The etymology we give
at 'eighty-six' is the one we'll stand by.  It is our contention
that the address at Chumley's is purely coincidence, and that the
word was developed in rhyming slang, and originally used by
restaurant workers so that the average customer didn't know what
they were talking about.
   "The earlier citations for 'eighty-six' [...] do not influence
our decisions about the etymology [...].  In fact, if the first
citation is from the early part of the range, it would tell against
the Chumley's hypothesis, as Chumley's did not exist before 1927-29.
Finally, because slang usually exists in the language for a number
of years before it is recorded, the existence of a citation from the
1920s tells strongly against the Chumley's explanation.
   "There are a number of other theories about the origin of the
word:  that it originated in the heyday of the British merchant
marine (the standard crew was 85, so that the 86th didn't get to
go); that 86 was the number of the California (or Florida) law that
forbade bartenders to serve the overly intoxicated; and that it
refers to the number of tables (85) at the New York restaurant 21,
and the table (86, in other words, no table) that the undesirable
got.  There are more, but the Chumley's theory is the most popular."
   "Eighty-six" is attested as a verb meaning "get rid of" from
1955 on.  It was surely in reference to this meaning that Maxwell
Smart, the hero of the 1960s sitcom "Get Smart!", was Agent 86.