It sickens me that these slick oil salesman seem to always find marks.

There are minimal damages (large driveway oil stain, cracked refrigerator shelf), but can I recoup the late fees from Aug?  

I currently live at home and work as an accountant for an oil and gas company.

You are going to suffer for quite a bit for before you can really turn this into a well oiled machine. 90% quit before they ever get there. 2.)

I hate getting guru advise as it always feels like fish oil tactics.

That's just the fundamentals1) Oil price.

I had a quilt at my STR that looked like a guest had set a paper plate of french fries down on it, and the oil was all over. 

You can paint over them with something like oil based Kilz to hide the stain and then ceiling white paint and leave the slight crack.

It could buy Delaware Statutory Trusts, or oil gas interests, or real estate syndications that would allow for tenants in common. 

But auto shops, particularly "backyard" shops are generally not the most careful with their used oils, brake parts cleaners, and other nasty chemicals that could be a real issue for your tenants and ultimately, you, the owner.3.