The exception to the rule that landlords cannot use “self help” to evict tenants is that the tenant has clearly and unequivocally abandoned the property. The problem in making this determination is that it is a judgment call. It depends entirely on the facts and if the landlord is wrong, there could be damages to pay. Unless the landlord is 100% sure that the tenant has totally abandoned the premises, it is always better to proceed with caution and file an eviction suit to obtain legal possession of the premises.
It may also be a good idea to communicate to the tenant in writing of their alleged abandonment of the premises. This writing should act as a notice of what actions will take place due to the abandonment and what time frame those actions will occur within. The Court is likely to see this as giving proper notice to the tenant and giving the tenant proper time to act accordingly.