Wait seven more hours for the epoxy to cure and to use the oven normally.

I assume this guy just has no backbone and is hoping you will issue a cure or quit notice he can send so he isn't the bad guy and can get rid of his situation. 

AFTER the notice to quit for lease violation (or notice to cure or however it's done in PA) has been served, have communication with her, only via text or email, never again orally, that you rented that house to 4 occupants, and that she is in violation. 

One of the inspectors referenced above has been known to kill deals over issues that can be cured.

The only cure is MTM leases and a 30 notice of non renewal for habitually late payers.

Joe's lease has provisions against this, so I properly serve him a "10 day notice to cure" using a process server ($$).

Tell them they have x days to perform under the contract (this called a notice of default and time to cure default).  

If it’s bad you explain that it’s a health issue that has to be cured.

Sadly, the cure for functional obsolescence is also price -- you have to discount for people to cure these "problems".  

If the current tenant is in violation of the lease you can give them a 'Cure or Quit' notice and possibly evict them.