Bava Batra 88: Honest Shopkeepers
A new mishnah! (the last of the chapter) -- on the upkeep of weights and measures. That is, wiping them clean, specifically those that are used for wet goods. Also, a question of ethical importance as determined by one's honesty in weights and measures -- supported by textual nuance. Plus, why it is that dishonesty in weights and measures is so bad.