I am a paperhanger in NJ and want to let you know I agree with you on removing the old grasscloth. When you cover over old wallpaper of any kind, you alter the integrity of the surface. You run the risk of adhesive failure over time which will result in cracking of the new surface. Removing the old grasscloth will return you to the original surface, which is always the most stable.
I suggest purchasing an adhesive solvent called DIF - available at Home Depot etc...
Prep the area to be stripped by taping thin plastic drop cloth to the molding right under the paper to be removed. This prevents water from soaking floors or carpets. Place newspaper on top of the plastic next to the wall, to absorb excess water that drips down. Then soak the heck out of the paper with the DIF and hot water. I use a 5 gal insecticide sprayer to apply the solution. Use a 4" bevelled spackle blade to scrape. Allow the solution to set for about 10 mins and then resoak. Again let it set. A few minutes more of setting can make a huge difference in how easily the paper comes off.You need to thoroughly spray the walls and rinse to remove all traces of adhesive before preparing to paint.
It is a good idea to test a 3" by 3" area before getting into the job. If the removal begins to remove the top layers of sheet rock, you can purchase the DIF in a gel, less water usually means less damage to old sheetrock. If it is a plaster wall underneath you should have no trouble at all.
All the Best!!
