Avodah Zarah 82
R. Yohanan said that they are prohibited because [the idolater] did not annul the idol. R. Shimon b. Lakish said that they are permitted because [the owner] can be assumed to have annulled [the idol], saying, “It could not save itself, so how can it save me!”
Now as to R. Yohanan, from the view of R. Meir we can infer the opinion of the Rabbis: Did not R. Meir say that images are prohibited but the fragments of images are permitted? Thus to the Rabbis, while an idol itself is prohibited, its fragments should be permitted.
But is the analogy correct? There [in the case of images] they were perhaps worshipped or perhaps not; and even if you assume that they had been worshipped, perhaps they had been annulled. But in the case of an idol, it has certainly been worshipped; and who can say whether it has been annulled? Consequently there is a doubt and a certainty, and a doubt cannot set aside a certainty.
[No] there it is a case of certainty and certainty, for he certainly tithed the produce, according to the teaching of R. Hanina of Hoza, for R. Hanina of Hoza said: It is presumed that a haver does not allow anything to pass out of his control unless it had been properly treated.