3,459. Throwing Away or Returning Vegetables
Hilchos Maaser 11:7
Let’s say that someone is carrying vegetables. His burden becomes too heavy for him so he decides to throw some on the road to lighten his load. In such a case, he must tithe them before he discards them in order not to place an obstacle in front of unlearned people who eat demai.
Hilchos Maaser 11:8
Let’s say that someone buys vegetables in the market and brings them into his possession, but he didn’t weigh, measure or pay for them. If he changes his mind and wants to return them to the shop, he must first tithe them.