I am moving into an older home. The garage and breezeway were turned into a dining room and laundry room years ago. They still have brick interior walls and the mortar is moldy in a lot of places---at least I guess that is what it is. It is black. What will clean it? Will muratic acid do it and is it safe to use inside. The next problem with the same rooms is the floor. There are three layers of vinyl on the floors and I have purchased some very expensive vinyl to replace what is there. I'm trying to do what I can to save money and the vinyl installer told me to remove all the old vinyl. I've been attempting to do so and the further down I get the worse the floor is. In one of the rooms, I've gone to the concrete in places to find that concrete was added thus there are seam lines, rough surface, etc. Now the installer says removing the old vinyl was a bad choice. All he can suggest now is putting down plywood with Liquid Nails and putting the new vinyl over that. Anyone got any ideas. I'm getting desperate!