
With a HINT of ammonia.
The Big Bang Theory Season 5, Episode 7

I'll give you a HINT,
The Big Bang Theory Season 10, Episode 5

I'll give you a HINT.
The Big Bang Theory Season 1, Episode 6

Hint: it's based
on Sanskrit,
The Big Bang Theory Season 12, Episode 2

Hint: it's a cube of a cube
of a prime.
The Big Bang Theory Season 12, Episode 23