The house smells like urine and after asking around, I've determined that it wasn't a pet but the elderly former owner.

Does the old insulation smell or any sign of animals being present? 

My ideal property is one where some or all of these major systems behind the walls or hidden in utility closets are brand spankin' new, but all the cosmetic stuff (the easy and inexpensive stuff that you can see and adds the most value) is just awful, worn, dirty, dated, cluttered, and smelling of cat pee and cigarette smoke.

For the vacant unit I want to eventually rent it out so I'm looking for advice and how to clean it up after a tenant leaves to get it ready.Currently it smells like the last tenant has been smoking inside the building.

We include this in the body of our initial rental agreement or create an addendum later if occupancy changes.

Tenant calls about the dryer in a 3 family smelling of smoke and then no heat.

I smell a troll

Hence, the tenant in Omaha that can qualify for a $400/month unit is nasty and smells up the hallways.

With a broken bulb there might be a smell too.  

Every body wanted to know what happened, local realtors, the HOA among others.