That stopped when I stopped using third-party cleaners, but I also started to only leave enough for the stay.I use a small Dawn hand dish liquid that I fill between guests and larger hand soap dispensers in the bath and kitchen that I fill between guests. 

Purchase price: $105,000 Cash invested: $90,000 Property needed some serious rehab, from trees roots destroying the basement walls, to plumbing, electrical, to roofing, landscape.

Do you think this issue is specific to banking services or what do you think is the root cause?

By all means give them a note on how to use all of the appliances (eg clean out the lint trap on the drier after each load, do not use dish soap in a dishwasher, change the furnace filter regularly, etc).

For STR's, is it necessary to get brand name hand soap, shampoos, and toilet paper? 

Something once a month or 2x a year that will help dissolve anything stuck.There are things that you can flush to deal with roots.

So can I calculate my cash on cash return like below $40K(appreciation)/($42k(Down payment)+(2.1K(Monthly payment for Mortgage+HOA)*36)) = 40/(42+75.6)= 34% so the annual cash on cash return is about 1.34 to find the cubit root.

I'm rooting for your success.Wisconsin Association Of Realtors License Requirements

So I have never gotten to the root of what people dislike about it.

That is crazy that there are not more 2-4 family in a market like Midland-Odessa with a ton of transient oil field workers that do not always put down roots.