You're spraying it on, right?

If there is a gap more than 1/4 inch between the Sheetrock and wall use spray foam to fill the gap and when it dries trim it away flush with a razor.

Changed the locks, and sprayed for stink bugs and spiders.

With the 3rd one I was the one who told him that for 1 end cap unit it is around the second RTU in the back, take a hose up there and spray around that really good, I don't care how long. 

I purchased a pretty decent paint spray gun, to paint the whole inside of my house. 

I have learned to get a cheap maintenance person and have them buy the good chemicals from A1 Able and spray it for you.

When you are doing some 35 campaigns, often 3 sets per day over 30 days you will be getting replys sprayed back pretty evenly. 

The companies that use heat treat in this area usually charge a lot more than chemical sprays.

I even outlined the spot in orange spray paint.

You can replace the tiles or spray them all for a fresh look.I would question having a 'Contractor' who mows your lawn doing other work.