Tohoros 8:3-4

Tohoros 8:3

If a person loses something during the day and he finds it that same day, it remains clean. If it was lost by day and found at night, or if it was lost at night and found by day, or if it was lost one day and found the next, it is unclean. The general rule is that if the night – or part of it – has passed, the object is unclean. If a person spreads out his clothes in the public domain, they remain clean; if he does so in a private domain, they are unclean. If he watched over them, then they remain clean (even in a private domain). If the clothes fell down and he went to bring them in (because they left his field of vision), they are unclean. If a learned person’s bucket fell into an unlearned person’s well so he went to get something to draw it out, the bucket is unclean because it was left for a time in the unlearned person’s domain.

Tohoros 8:4

If a person left his house open and returned to find it open, or he left it locked and returned to find it locked, or he left it open and returned to find it locked – in all of the cases, the contents of the house remain clean. If he left it locked and returned to find it open, Rabbi Meir rules the contents of the house unclean. The Sages rule the contents of the house clean because, even if burglars had been there, they might have changed their minds and gone away (without entering the house).