The landlord should make a reasonable effort to contact the former tenant. If the landlord has not heard from the tenant or is not aware of the tenant's intention to not abandon the property, the landlord may proceed to sell the property in accordance with law. The landlord may also have the property removed from the unit pursuant to the execution of a Writ of Restitution. This method of property removal and disposal is the least likely to result in liability to the landlord.
If the abandoned property is a motor vehicle, different procedures must be followed. Contact an attorney or the local law enforcement agency.