Check her out... she's hilarious!
(this is the description under the video)
Tiny yorkie mix/mutt successfully searches out and finds "drugs" hidden in houseplant. The "drugs" are actually nothing but peppermint tea leaves. Notice how she checks, but does not play with the tennis balls on the floor. These balls are identical to the one that she gets at the end as a reward. The reward ball, however, has been sitting for a few weeks WITH the peppermint scent, and she only ever gets to play with that specific ball after she has "found" the scent.
I trained her to do this in less than an hour. She is a very willing working dog-- too bad she isn't larger. She will jump up on furniture to sniff shelves, and climb all over objects and into them trying to find the scent. This is Nutmeg, and she is 2yo.