I had quite a few that stayed after they graduated, sometimes for several years, even in tiny studios.  

Some sort of oil based paint on the sub floor if it's wooden, and if the stains are fairly limited.If it's concrete, maybe bleach.I don't know about fleas, wouldn't most of them go away when you rip out the carpet?

The property I managed was a 26 unit, 2-story single building, no frills, no balconies, showers only, old building, high ceilings, no elevator, with mainly tiny studios (about 250 square feet).  

Usually when requested and I try to get a tiny bit more rent for them with a provision in the rent that I am not obligated to repair or replace them if they quit working.  

It was a 26 unit building, mostly tiny studios, so I rented separate units.You know who is renting separate rooms to med students now, though, is @Al Williamson .  

@Jil Tin I think it would be a tad crazy to buy a million dollar home now, when you want to retire in 12 years.  

He only discovered 2 tiny issues during the final inspection.

I discussed it with the owner and we decided against it at the time, because the building was such tight quarters with lots of tiny studios and lots of grad students who needed it quiet - and we weren't sure we could count on the corporate apartment being quiet.But, there's a market for it.

Am planning to rent to people with tiny houses as a way to off-set my holding costs.

I sent them all texts apologizing for wasting their time with those tiny checks.