Hired a contractor to remove wallpaper, plaster and paint living room and hall. He says having put two coats of skim coat--in some areas with mesh--he's ready to sand tomorrow. However in looking closely at the work, I've found mesh showing in dozens of places--meaning to me there's only one layer of skim coat, some very sloppy work uner the windows and near stairs, and some hardened drops from the plaster weld that were allowed to drip. Where it looks sloppy I'm guessing he mixed in extra plaster for strength which then dried before he could smooth it out. Is this all correctable by sanding? Surely if the mesh is visible now, sanding will make it more visible. I hope i can attach photos.