Or own a time machine? 

@Matt Gilroy I own apartments in Indiana which are C- class cash flow machines.

Today banks are giant machines that bundle and sell billions of dollars worth of collateralized mortgages on the secondary market to hedge funds and institutional investors.

Too expensive for a rental, but what you described is exactly how these machines are expected to be used.

I had a washer/dryer combo unit installed as I didn’t have room to stack machines. 

So yes, at some point things like the water heater and laundry machines DO make a difference.

You do not pay Starbucks an extra fee because they used their coffee machine to make your coffee.

The rent increase pays for the machines and infrastructure within 2 years, and the apartment is much easier to lease when it has laundry included.I am not sure how much I'd like tenants hauling appliances in and out of our apartments, and being responsible for hooking them up- they do enough damage just moving furniture!  

We bought 10 bags, got a free machine rental from Lowe's and blew it all in within a couple of hours.  

So, rent a machine that removes odors - forget what it's called - but you can rent machines that do this - ozone machines?