How soon can I legitimately send Notice to Pay or Quit

[Yvonne H.]

I'm in NC. Rent is due on the 1st. By law, we cannot charge a late fee until the 5th. I have some troublesome tenants who need to be dealt with accordingly and most of all swiftly.
My question is, can I send them a late notice on the 2nd of the month even though the late fee is not in effect until the 6th? Or do I have to wait until the 6th?