Tuvia was walking by Mr. Pachman’s house and noticed an almost new toaster oven waiting for garbage collection. It looked to be in good condition, so Tuvia took it home and tested it; it worked fine.
“Why did you throw out your toaster oven?” Tuvia asked Mr. Pachman.
“It was milchig and someone heated a patty in it,” explained Mr. Pachman. “He thought it was pareve, but the patty turned out to be fleishig. I heard that you can’t kasher a toaster oven.
“I’m not sure that’s always true,” said Tuvia. “When was the oven last used for milchigs?”
“It wasn’t used for a few days,” answered Mr. Pachman.
“How was the patty heated?” asked Tuvia.
“On aluminum foil,” Mr. Pachman answered.
Tuvia looked inside the oven; it was quite clean. “There was barely any splattering,” he said. “I’ll check with Rabbi Isser.”
“Under these circumstances,” said Rabbi Isser, “you can kasher the toaster oven by turning it to the highest setting for half an hour.”
Tuvia called Mr. Pachman and told him what Rabbi Isser had said.
“That’s good to know,” Mr. Pachman said. “If the toaster oven can be kashered, though, I’d like it back.”
“But you threw it out and disowned it,” said Tuvia. “It was waiting to be picked up with the garbage collection. I acquired it from hekfer.”
“But that was a mistake,” said Mr. Pachman. “Had I known that it was possible to kasher the toaster oven I would not have thrown it out.”
“Had I not checked with Rabbi Isser, though, it would have been collected shortly by the garbage men,” replied Tuvia. “I’m happy to discuss the issue with Rabbi Dayan.”
“If Mr. Pachman threw out a toaster oven because he mistakenly thought that it couldn’t be kashered,” asked Tuvia, “can I keep it?”
“A similar question was posed regarding fat that was disposed of because it was thought to be forbidden cheilev, but was actually permitted shuman,” replied Rabbi Dayan. “Similarly, candles that were disposed of because they were thought to contain a forbidden mixture of butter and meat-fat, but later verification confirmed that there was no butter.” (Shemen Hamor C.M. #1; Mor V’Ohalos Y.D. 4)
“At first glance, it would seem that you should have to return the toaster oven,” continued Rabbi Dayan. “Mr. Pachman threw it out because he thought he could not kasher it. Tosfos writes [Gittin 47a; Pesachim 57a] that hefker (disowning) rooted in error is not hefker, just as a gift or transaction rooted in error is not valid [C.M. 246:1-3]. Similarly, pe’ah that was mistakenly given to the poor from vegetables that are not obligated in pe’ah are not considered hefker, since the gift was rooted in error.” (Pesachim 57a)
“Why do you say at first glance?” asked Tuvia. “It seems pretty clear.”
“There is a seemingly contradictory source,” said Rabbi Dayan. “The Gemara [Kerisus 24a] teaches that if witnesses testified that an ox gored and killed a person or that a city was an ir nidachas, which renders the property forbidden, and later the witnesses were proven false, then whoever seizes the property acquires it. The owner already relinquished ownership of the property, even though it turned out to be rooted in error.”
“How do we resolve this contradiction?” asked Tuvia.
“The issue is somewhat complicated,” replied Rabbi Dayan. “Some differentiate between one who gave to others based on a mistaken reason and one who disowned his property completely where the error is not likely to be discovered, such as in our case. Since the owner fully severed his connection with the property, even if for mistaken reasons, it’s gone if the error is not likely to be clarified. Some also compare our situation to yei’ush [abandonment] of lost property. Also, Mr. Pachman could have asked a shailah before disposing of the toaster oven. Thus, you can keep the toaster oven if you wish.” (See Pischei Choshen, Kinyanim 23:39; Aveidah 2:8)