I am removing wallpaper that has been hung probably over 20 years ago. I am going to use a Dif to dissolve the glue and then do all of the hard scraping work. Does anyone know which product is better the liquid Dif you spray on or the gel? Also, any other tips on removing the wallpaper as this is a difficult and time consuming task and any help would be appreciated. Thanks to all.

I have removed some wallpaper from my hallway. Actually, it removed itself--it was probably about 20 years old, and was falling down, I just gently pulled it off. The surface behind it has me confused. It appears to be the same color as the painted trim around the hallway doors. There are some areas here and there which appear to be paste, all crumbly. There is some kind of dark brown stuff on the walls, all around the edges of where the paper was stuck. My question is.... how do I know what is glue and what is not? Would the entire wall have been covered with glue, or just the seams? No, I have never done this before, I have no idea what wallpaper glue looks like. I have also never heard of wallpaper that just falls right off either. I did not need to use Dif or anything to get the paper down. My concern here is that I want to remove the glue, in order to paint the walls. But I do not want to waste my time scrubbing surfaces that don't have glue on them. In short, what the heck does wallpaper glue look like??????????/