You didn't make mention of the use of a Paper Tiger. Its purpose is to perforate THROUGH the paper and backing right to the drywall. (You should press just enough to get through to the drywall/plaster.) Then, I use one of those HUGE car washing sponges to apply the solution. I know how thorough you are but did you re-READ the directions to be SURE, absolutely sure, that you're doing as it says? I love the stuff. I was generous with the mix, making sure it's ALWAYS fairly clean AND HOT! I've used gloves and kept that tea pot on a low, rolling boil as I did the job. I ALWAYS had HOT water. And I never try to do too much at one time. Again, the directions are clear.