I think that's a question for the hints and tips thread.
They're in the fresh air cavern, to the far right. Unless you already picked them up and dropped them somewhere else.
And thanks so much, everyone! Yeah, the last couple of days have been extra crazy and busy for me (who said everything's over the moment your game is released, huh?), but man, we're absolutely floored by the amount of positive feedback we've received so far!