Pretty good system and we have been bone dry ever since.Part of that process involved removing the drywall up four feet from the floor and while it was removed I scrubbed any areas that looked dirty or moldy on the cinderblock in accordance with CDC guidelines for mold removal (actually double their guidelines since I scrubbed it with bleach and water once and then a few days later again with detergent and water).  

Mix a solution of 40% bleach 60% water and add 1/2 cup of dawn dish detergent .

Drop or two of detergent in the water.

If you Google this, there's a lot of suggestions:1) Super clean by Castrol2) Let kitty litter sit on the stain as long as you can then after you wipe up try some ultra dish detergent to let sit for a few days3) WD-404) Oven cleaner

How about grading roads, picking up trash, mowing, flipping the bedrooms, sheets, towels, pillows, mattresses, silverware, detergent, new vacuum cleaners, etc. 

You should also have a dishwasher with detergent and a rule- all dishes cleared up.5) In general run this like it is an Airbnb. 

They may as well be trying to re-sell boxes of detergent out the back fo their vans (assuming they're old enough to get a drivers license much less a RE license).You sound smart, just promise you'll learn to do things the right way and not rely on subterfuge. 

One bottle on each kitchen counter beside the Dawn here, Paul, and a spare bottle in each laundry room on the shelf with the detergent. 

., laundry detergent, dish detergent, paper towels, etc.

I have a shelf in the laundry room where they can leave laundry detergent and softener, but it's at their own risk and I'm not responsible if someone steals or uses it.