OK, I have to repsond to this thread! My wife and I wallpapered every room in our house when it was in vogue. Then, of course, when the wallpaper became tired or out of style, we changed it or removed it all together.
We have used DIF, and in most cases this stuff works well, especially when sprayed constantly from a bottle.
Well, a few weeks ago we did remove the Vinyl Wallpaper from Hades! As Sadam would say, the mother of all wallpapers!
We used the tool to craze the surface, sprayed DIF, and waited a few minutes. Pieces of vinyl began falling off the wall -- one inch at a time!. Then the backing had to be treated just like the outer surface. What a job!
My first response was to pour gasoline of the wall and burn this stuff off, but that would leave the adjoining rooms reeking of gas! So, I got out the big guns -- the steam cleaner wallpaper remover!
There are lots of these babies on the market, the one we used was a Wagner. It is so much easier than the old propane tank steamers that you had to fire up outside your door. Plug it in, add water, and let 'er rip.
Wow, do they work. Now you just soften the paper backing, and the paper comes off easily.