Can anyone supply the origin of the terms "brown nose" and "brownie points", which I presume are related?

(I ran into a historical tidbit that suggests a source - but only if I add to the data a "guess" from which to leap to a conclusion.)

To keep this interesting, may I suggest that this question be a "no OED" zone: we pick our own collective brains and, for the moment, bar any look-up in word-related sources?