Yup coffee can neutralize odors... some perfume boutiques have some coffee grounds for those who test the scents of the perfumes. After smelling one perfume, you might not be able to distinguish the scent of the other perfume... smelling the coffee grounds "resets" your sense of smell.

In Italy, kung magluto daw ang mga pinoy ng daing o tuyo, para hindi magreklamo yung mga kapitbahay nila sa amoy, sinasabayan nila ng pagluto ng kape. heheheh

And yeah, you listed down the other benefits of used coffee grounds.