How to tell someone that they've overstayed their welcome?

[keep positive 24/7]

There's a couple of nerds smoking doobies on my porch.

Ok, ok... I did say that they could do it. But that was months ago! I'm sorry, but they've got to go.

What should I do to ensure that this interaction goes as smoothly as possible.

 

[The Grinch]

Tell them you are expecting a visit from relatives in a hour. Might as well tell someone to call you so you can pretend that it’s a relative who is going to come to you home

 

[Suimaxxer]

Kill them