If you want to deduct money for cleaning, hire a cleaning company (which I know you said you don't want to do). 

He's fast, clean and priced right for labor.  

I finally paid a guy $2K to empty it and clean it up a bit and sold it through a wholesaler for $10000 to a young, big-talking investor from out-of-town who was positive that all he needed was some basic repairs (that he confidently told me he knew all about).To date, that property is still under renovation.

here are some things I personally did on my last one (which didn't appraise, so I sold it):-the demo-cleaning out junk in the garage dating back to the 1950s-mowing the lawn when it got 0.1" past the neighbors' liking-called 37 contractors to get 3 bidshttps://www.zillow.com/homedetails/108-Ellsworth-Ave-Elizabe...

For example,Late RentInsufficient FundsUtility ReconnectionReissue CheckA/C Clean ViolationPest ControlRenewalMove-Out AdministrationUnlock RequestKey RequestFailure to Return KeyPilot LightingGrilling ViolationGarbage ViolationClogged Drain / Tub / ToiletWindow ScreenHurricane Shutter ViolationSmoking ViolationLease Amendment AmendmentPet ApplicationUnauthorized PetGuest ViolationUnauthorized OccupantInspection (due to tenant violation)Yard RemediationPool RemediationSmart Home Device TamperExterior Maintenance ViolationParking ViolationCommunity Amenity ViolationMarketing (tenant early termination)Notice (due to tenant violation) PreparationNotice DeliveryLien ViolationSubleaseAssociation ViolationEviction (not including attorney’s fees and eviction costs)Rent Verification10.

Hello we just had tenants move out and their standard of cleanness makes me want to laugh.

I'm hoping someone will clarify...RentsAdvertising / Auto & Travel / Cleaning and maintenance / Insurance / Legal / Repairs / Supplies / Taxes / UtilitiesMortgage interestDepreciationFor long-term rentals...what would be an example of CoGS?

If you seriously want to clean this up and are willing to take a risk, I would absolutely switch things into my name and begin taking care of the property as my own...it takes up to 10 years, but if you'd be willing to start caring for the property and were able to at least rent as a break even, pay taxes etc, then it's no big loss if the owner came back and stopped your claim.

They are drained and cleaned after every guest.  

It is a clean slate walls-and-studs-only building.