Usually there will be at least one low hanging fruit- the guy that will take the cash.

Their washer machine failed and dumped all the water out.

@Drew Reynolds   my goal would be to build a brrrr machine.

If they don't pay rent on time they would always have the option of paying the parking meter machine.

I'm not just offering myself up for free, unless the right mentor relationship presented itself, but I would love to sit down for coffee with a few people one on one and see if we can start a fruitful relationship.Just let me know if you have any interest in getting together and see where things lead. 

Personally when I rented I was always rolling my eyes when I saw a coin-op machine in the building and felt like that was just an extra hidden cost into my rent.

1 of my tenants has either fruit flies or Drain flies.

The house also needs freshening up (it's a time machine to 1982).

It took me about 1 hour and I was done . now I have lots of time to get a replacement the spare covers the current  problem .I dont repair refrigerators , washing machines or dryers , its cheaper and faster just to replace .

Odoban, as well as an ozone machine, may help.