TweetActually, go one step further and break them before throwing them away. In other words, DESTROY ANY EVIDENCE!!
Even if you discard empty unlabeled vials, if someone suspects something then they can have any little bit of residue found in the vial tested. God forbid should there be some sort of identifiable items in the trash with the vial, such as discarded mail or letters with your entire I.D. on it. Then it would be known where the vial came from.
As for the labels, place them in an envelope and shred it. End of story, no more evidence.