Do you have any language in your lease defining abandonment? If so, what is it?

Who gave the notice - you or the tenant?

Have you left messages for the tenant? Do you have a forwarding address so you can mail notice of your intentions to the tenant? Have you tried posting a notice on the door? If you've done any of the above, did you tell the tenant that the premises appear abandoned and that as of a particular date you'll remove and discard any remaining items as garbage? (What, if anything, have you stated to the tenant?)