Hello,I had a partly damaged wooden floor in one of my rentals five years ago but I did not do a good job back then  hiring the right contractor as I was a noob and back then they installed prefinished flooring with completely contrasting very dark flooring stain, also while they ripped  of the flooring in the room they applied it as a patch  in one of the sections in living room where the flooring was damaged. 

Since you don't know what the grease and stains are from...

The public seizure of the Bruce's Beach property has long stained the history of Manhattan Beach, particularly in the past year amid a nationwide reckoning on racial injustice.

The place is gross, crumbs and stains everywhere.

I'm in the processing of purchasing a house and the inspection found water stains on the wall between the master bedroom and the bathroom next to it.

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.

If there are holes in the wall or other stains and marks then yes that can be deducted4.

They burnt so much incense the walls were soot stained.

It had no gutters at the time so there was some damage to the foundation and significant staining to the siding.

Neighbor (the owner/landlord) below my condo unit has complained about leaks from our unit several times claiming that it has resulted in potential molding and other serious issues even though we only see some small brown stains and drops of water in the kitchen and bathroom area.