Encountered a new situation with tenants....lawyers advice seems like it may violate tenant rights...advice?

[psu176]

I had rented to a couple who split up in August (only 6 mo into their yr lease). they owed rent for August then neither (not even the partner who stayed at the apt) paid for Sept. She informed me that she was planning on moving (I explained she was still responsible for the rent and if she broke her lease there is also a penalty equal to a months rent as well as the late fee she has already incurred for not paying rent-its all outlined in the lease)

Around Sept 10th the partner who had left came and took a truckload of belongings. On the 15th the partner who lived here took a couple loads of belongings. She never returned until yesterday. I had called the abuse program that was helping the partner who left and explained that I needed a msg relayed to her stating that the apt was dirty smelly and infested with fleas it needs cleaned and there are still a lot of her belongings still there) that evening both girls came and took a truckload of clothes.

The apt still has some belongings. My lawyer advised me to give a 30 day eviction (not through the court). This will be up on Oct. 10th. The problem is that the apt is truly infested with fleas (they had multiple cats and a dog when they were only to have a dog. They admitted not treating any of the animals for fleas. when you walk in you are literally covered with fleas). Beyond this the apt is dirty. I saw bugs and I am worried about roaches. My lawyer told me I can go in and put all of their belongings in one room, clean up the garbage and food, and bomb for bugs.

I feel funny doing this like I am violating some rights or something. I figured sending a certified letter to them stating that on a certain date we will be bombing and cleaning and if their belongings are still there we will move them all into the living room (the least infested room). I know that they did not leave a forwarding address at the post office however I do believe they are picking up their mail as I have been watching their PO box. Has anyone had a similar situation? Am I approaching this wrong? Should I follow my lawyers advice? (I was also told to go ahead and change the locks even though the eviction isn't up yet but since they moved out. Can I do that?!!!
I am in PA.