Top Secret Communications Center

When my son was in the Air Force, my wife and I visited quite often.
On our first visit, we were allowed inside this top secret
Communications Center, but everything in sight was covered up so we
could look around everywhere -- Heck, even the toilet paper in the
Men's room was disguised.

Anyway, at the exit, there's a sign above the door, which reads: "You
have been exposed to Top Secret Material. Please destroy yourself
before leaving the building."