In my former career, I interviewed many highly educated people  - doctors, attorneys, judges, engineers, etc who were taken to the cleaners by scam artists - yet they refused to believe that the "investment" wouldn't pay off - they couldn't bring themselves to believe that they just flushed a fortune down the toilet - The fees associated with the "Mastery" program or any other GURU course is nothing more than flushing money down the drain - All of the information provided is readily available for free in many formats - what the student "investors" are paying for is someone to hold their hand while they jump in the pool - someone to make them feel like they have an edge that then gives them the confidence  to take that scary first step - to answer your question .... definitely Fortune Takers

I have thought about using a small amount of liquid sewer or drain cleaner periodically, but I don't want to do any damage to the not new cast iron pipes.

As long *** there aren't any dry cleaners, chemical manufacturers or gas stations close to you, there is likely not an issue.

If you hire a cleaner and deduct from the deposit,... that might stick better if you want to try to withhold the deposit (and take it to court if need be).I've had tons of roommates.

This ruler did not want to do so because the rivers at home were soo much cleaner than the Jordan.

Now it's just still overcrowded, the air is cleaner :)

PM hires cleaner who charges much less. 

For restaurant owners, hotels, grocery, hair salons, dry cleaners, all retail centers.....and real estate investors BAD!

An unethical person will take you to the cleaners by telling you they are "green," then take that stuff to the landfill.

Your janitorial subcontractor uses a cleaner that causes the tub to be too slippery, they fall and hit their head.