Be a bit careful on any of the aforementioned advice. Most of it is factually incorrect.

If you took any money from them, it is considered rent and they have a right to occupy the premises. You cannot simply go over and kick them out as if they were "guests".

They are currently "tenants" and you must follow proper procedure to evict them. This requires you to go to court and obtain a warrant to evict which, here in NY, is executed by the sheriff.

The fact that they have no lease simply means that they are a "month to month" tenant, with all the rights of a tenant. You cannot physically toss them out..........you cannot remove their belongings............and you will get no assistance from the police.