A letter of abandonment of property is the legal notification that allows the owner of the abandoned property to recover their goods before they are disposed. By law, if someone is in possession of another person's property, they can't dispose of it without legal notice to the rightful owner.
There are rules when it comes to rental property. When someone moves out of an apartment or home and leaves personal property behind, the landlord can't dispose of that property without notifying the owner. This gives the rightful owner a warning that the items will be discarded unless someone comes to claim them.