Accepting cash is a big and risky effort, as there are so many ways an error can occur, through process and procedure, and all caused by the mere fact that cash is involved.  

It may be worth it to contact an attorney to review the history and have them show you the procedure on how to kick them out. 

As soon as it is late, follow your state's procedures- here we can serve a "Pay or Quit" notice in person to the tenant or any occupant over 18, or we can mail it which is what I do since it means I don't have to track down the tenant.  

Our procedure is that we encourage everyone to apply, just for the simple fact of what you stated before.

Since I didn't place the first one so I'm not stressing that one, but the second one is a result of me deviating 1/2 an inch from my standard procedure.  

However if there is any issue I would make sure you follow the lease agreement to the letter and do not deviate or go off of your "Gut Feeling"... just stick with your policies and procedures and you should be fine

I have never done something like this before so I was hoping one of you experienced land lords could guide me on a procedure.

Confirm with your state landlord tenant regulations as to the proper procedure for taking back a unit.Since no response to your question has come from a landlord in your state you can not be sure of the process.

If you choose not to you should expect eviction procedures to be started.

Convenience is a big factor in RE, so cash for keys is a very common procedure.