I also had a situation where the upper jet wasn't working.

Buy a jet pack.

Sweating an asset to maximize profit applies to jet airliners, nuclear plants and paint. 

If they did big patches using drywall compound you can probably just wipe them and remove them with a wet sponge and then fill, not patch the holes and touch up and be on your way.We had a tenant do something like this a long time ago, they patched over their tiny nail holes, turning a 1/16th hole into a 4'-5" god awful mud smear over textured walls, they then for some reason primed over the patches, that was considered damage to us, as it required retexturing the walls to blend in the patches and then repainting the entire walls, the patching cost that tenant about 2K.

Nevermind that there's nothing wrong with the bathroom, she just wanted a jetted tub, tile floors, and a new vanity she saw at home depot.  

Clear jet engine storage containers

Which included demoing the back porch, new HVAC, new electrical, re-sheet rock with tape texture and paint, kitchen island and counters. 

Other than that, I'm not too familiar w/ Worcester just know that it has a couple of colleges, major hospital, has recently upgraded the ""T" access to Boston, and Jet Blue has added it to it's areas served so we feel it is a strong market w/ potential.

I had renters paint my perfectly smooth walls with purple 'textured paint', when they moved out they tried to tell me this was an upgrade and that I should be paying them for the improvement.  

The drain cleaner snakes or jets the line and rarely are they able to see the items flowing past.Also in some cases it's a combination, it could be an old cast iron pipe with a rough inside surface full of rust, which started to act like velcro to things that flows past, or a slight settlement causing a belly, which again impedes the flow, then the tenant pours down grease, pasta and bean, well, you get the idea.Most of the time you end up eating the cost especially if the plumber can't tell you anything.Now, you mentioned that the clog caused water to back up to a vacant unit next door.