Bathroom was previously papered. I took off all the paper and I can't feel any glue(used a steamer) but there is what appears to be sizing on the wall. I need to skim the wall over damaged area prior to painting but do I have to do anything about the sizing? Also have a corner with metal reinforcement. It looks like it never had tape over it, alot of metal showing. So I figure I must have to tape over the metal and mud so paint will stick.