tenant moved out left property

Tenants moved out on Oct.14th, they kept returning for a week to pick up odds and ends. By Oct 30th they finally returned the key. They knew they left a futon mattress, wastepaper basket and 16inch chrome statue. I have no forwarding address for them although I know they still live somewhere in town. I asked the mailman and he had no forwarding address for them either. They have an unlisted phone number. I even tried to call her job but they said she no longer worked there. I had told the boyfriend when he was coming back and forth to get mail about the items left and still they have not been removed. How long do I have to keep the items before I can dispose of them.

Give them 30 days notice (in writing at last known address) and inform the police as well. You may dispose after that.