If mold is on the joist that would be no problem to clean, just needs some equipment and on the sub floor i believe pending on how severe it is you may just get away with a cleaning with specialized chemical thats stronger than bleach (I know the name but cant remember how its spelled) , as well as a negative air machine, some duct tape, plastic sheething, tyvek suits, gloves and other ppe needed for the workers or it could be severe enough that the floors would have to come up (I know you dont like the sounds of that) and possibly trace it up the walls if any moisture wicked its way up sheetrock and the insulation thats in the walls?...

There are special primers for the walls to encase the cat (or dog) smell from this--which is an option.With a floor like this, with about a million high heel divots from 1890 until yesterday, and a finish that has reached the end of its service life, the discoloration is not such a problem, if you intend to put in pet resistant carpet and padding, it will be covered.An alternative would be to sand it down and refinish it to look like a refinished floor...they never look like new because they use chemical clear coats now vs Varnish or shellac like the olden days.Even with sanding the dog stains may need to be bleached out, and may still have trace shadow that they were there.Why is it a computer nook, well it doesn't have to be.

Does anyone have any creative ideas of how a city and local investors can work together to ensure that all properties are safe, habitable and reasonably well-kept without instituting such a harsh, blanketed ordinance meant to keep some of the 'bad apples' in compliance?

I feel your pain.I’m a female and new to REI as a business.However, I’ve always handled contractors for my primary residence, and I’ve worked in several industries - industrial chemical sales, bartending/waitressing, and I’m now I am a chemist with a PhD.All that to tell you that male chauvinism is rampant anywhere you go.

@John Thedford  think you have been a little harsh on @Angie A.

Try some of these threads:http://www.biggerpockets.com/forums/84/topics/45246-mold-questionhttp://www.biggerpockets.com/forums/88/topics/41433-mold-http://www.biggerpockets.com/forums/67/topics/31237-mold-and-rehabbing-simple-or-complex-http://www.biggerpockets.com/forums/103/topics/28752-short-sale-house-has-mold-would-you-use-to-offer-low-If you insist on a DIY effort, then get the proper chemicals; believe it or not, the local big box hardware stores have a number of these in stock, and by reading the labels you can figure out which one might be the best fir for your situation.

I find your opening statement a little harsh.

For example, many CA people will tell you how they would never move to xyz state or states because of lack of jobs, lack of diversity, lack of scenery, conservative mindset, harsh weather etc etc.

The new finish will wear off, especially if they use a harsh chemical cleaner.

The better deals sell within the open house period and the rest are junk to me (maybe that's harsh but again my opinion).