Demai 6:6

Beis Shammai says that one should only sell olive trees to a learned person (who will protect the produce from ritual impurity). Beis Hillel said they may be sold to a person who tithes (but who doesn’t know about ritual impurity). The more zealous members of Beis Hillel followed the stringent opinion of Beis Shammai in this matter.

Demai 6:7

If two partners harvest their grapes in the same wine vat, and one of them takes tithes but the other doesn’t, then the one who tithes takes tithes from his own share, which is wherever it may be.