Easy to use straight bleach on a tough stain after washing.

Pour bleach down the drain pipe because the line will eventually clog up and the water can cause a lot of damage. 

Bleach and gasoline mixture would be good.

YEP -- he grabs the wrong bottle (it contained bleach) and spot cleans several rooms of the house (5 bedroom home), and totally ruins all the carpet in a 2,800 sq ft home.  

I'd wipe the floors with some bleach and call it a day.

Bleach does not kill mold.

Not sure how extensive your mold problem is (sounds like it is), but I know you can buy mold killer or just do a bleach and water mixture and spray it everywhere.

I had this happen to me as well when i did that on a wood floor one time, but it cleaned right up with some bleach water, and never had any issue with mold in that space afterwards.I had googled it at the time and it appears to be really common when placing mattress directly on the floor. 

However, my house is on a short, dead end street with only two other houses and a mobile home; there's no city sewer line available and no plans to put one in in the near future so nothing to "tie into".At this point my goal is to limit the number of people living in the house (to reduce the sewer "load"), provide them with products containing bacteria to flush down the toilet once a month (no guarantee they'll do that), include a clause in their lease to limit the use of bleach and ammonia that would kill the bacteria in the tank and a regular (once a year) clean out of the tank.Gail

Is there some magic cleaning tip I'm missing, because Oxyclean, hot water, and bleach aren't cutting it.