It had some water staining, so I am sure there was a spill at one time or another. 

I refinish furniture and mainly use a sponge to apply the stain.

The carpet must have several unique stains, because usually all it takes is a few washes with our carpet cleaner to get it done.

Alternatively, fine sawdust works almost as well.Once you've done as he suggests, I'd mix Dawn with very hot water and scrub out the remaining stain that's absorbed into the concrete.

Concrete floor on that could easily be stained to look great out in the open! 

I plan on purchasing my first rental property within the next year as well as staining my real estate license.  

Have you thought about using a solid color stain instead of paint?

I did everything from drywall repair, to tile, to kitchen cabinets to sanding staining floors.

I have a small dog who is impeccably house broken and never once went to the bathroom inside, although there was a small stain from a time when he vomited.

It seems like fair common sense that an additional 4 animals of the same type would not provide much addition emotional support however quadruple the chance that the landlord will end up with urine stains on their flooring.Its a bit of a free for all at the moment it seems.