To '86' something is to render it unusable. The AIEE-
American Institute of Electrical Engineers employs the use of a lockout relay that turns the equipment off--Like
tripping a breaker (for those who have trouble understanding, imagine blowing a
fuse). It turns whatever you're using off, therefore "86-ing" it. It's been in use nationwide since 1928, so it's plausible that the term may have originated from electricians!