If I found 1 shoe. Do I need to return it or call it out?
Before picking up the shoe, the answer to this question depends on where the shoe was found, and on whether or not the shoe has characteristic markings by which it can be identified. However, having picked up the shoe, and providing that the place at which the shoe was found is a place whose frequenters and mainly (51%) Jewish, you should “declare” the loss by putting up a notice at the place where it was found, announcing that a shoe has been found, and giving contact details. You should then return the shoe by relying on the identification given by the caller, the best form being the presentation of the other shoe in the pair.
If the shoe is badly damaged, or looks like it has been thrown away and discarded, there is no obligation to declare it.