Hi--I would imagine it would be easier to remove wallpaper from plaster walls than sheetrock. Some people swear by wallpaper steamers, and if that sounds easiest to you then check it out. I've never used one before, so I can't say. My own experience removing up to 14 layers of old wallpaper from the plaster walls of our early 1890's home involved scraping off the outer layer(s) of stiff, painted-over paper with a razor scraper, and then using a warm solution of DIF wallpaper remover rolled on with a paint roller on the remaining layers, scraping it all off with a putty knife and razor scraper. It takes time, but it really depends on the papers/adhesives used and the condition of the underlying plaster. The remaining glue and remover residue is then washed off with TSP. Expect some cracks and other decay in the plaster, and understand that old plaster can look really-really bad and still be salvageable, depending on how much effort you want to put into it. Our repaired plaster walls have some imperfections, and I came to realize that it was unrealistic to expect that they'd ever have the perfectly smooth appearance of sheetrock walls, but I love them all the same. Good luck and don't get discouraged--old plaster walls that have been saved are a wonderful surface and you won't regret bringing them back.

Been there and done that a hundred times with wallpaper on plaster walls. I'm in my eighth house now where I've had to strip paper. I used to rent a steamer but just bit the bullet and bought one. That's what I always end up using when I get tired of fighting ancient wallpaper built up with many layers. All of which have been on wet plaster walls. Steamers don't work as well with new wallpaper using plastic, since obviously plastic is waterproof and the steam doesn't sink in. But those are designed to be dry strippable. A laugh, but most of it will strip dry. Then I attack with a steamer.

Once the paper is off, as the previous poster says, you clean the glue or sizing off the walls, and if you find imperfections (and that is often why paper is up in the first place, as a quick fix) then you learn how to sand and mud walls. It's like icing a cake and I am to the point now I can skim coat a finish without even having to resand.

try this site

Here is a link that might be useful: stripping

I have plaster walls, all of them were covered with wall paper. I agree with the others, steaming works the best.. much easier to remove from plaster than sheet rock!
Ree

The key to removing ANY wallpaper is to score the paper BUT not so deeply as to cut the wall underneath.
THEN you can use either steam, vinegar and hot water or CHEAP Downy fabric softener and hot water.

Spray the wall after scoring the paper and let the spray sit for ten minutes. Use a putty knife or a razor scraper. While you are working on one area spray the other work from the very top to the bottom. Cover the floor with plastic or and old sheet.
The key is to keep the paper wet. The fabric softener or the vinegar help neturalize the old glue so it will seperate from the paper.

"The key to removing ANY wallpaper is to score the paper BUT not so deeply as to cut the wall underneath. "

On plaster you can either remove the paper dry using a 4 inch razor scraper or if the paper had not been painted just use a steamer.
If you scrape it often is simpler to go back and steam any slight remaining paper.
It is fast and there is very little damage to the plaster.
Even with drywall a steamer works very quickly on unpainted paper.
Painted paper on drywall can be a chore and requires scoring the paper, but a steamer is far less likely to damage the surface of the drywall than spraying water all over the place (with any additive).

The idea is to minimize the amount of moisture you are spreading around.
It is hard on floors, woodwork, and even drywall.

I had the same problem in my house. using a paper tiger perforator is the best tool to use to perforate the paper so your steam or water will loosen the glue better and not cut in to your wall. I found steaming the fastest and cleanest way to remove wallpaper. I found I could buy a steamer for less than renting it to do my projects. the local rental place wanted $30/day and I found I could buy a Wagner wallpaper steamer at Lowe's for $50. so far I have used the steamer several times so its been worth it to buy one since I have several more rooms to do.

The only disadvantage to the Wagner is if you have small spaces to remove paper from you have to order the other head for the unit.
I know I have some spots over my doors and windows that are narrower than the head that comes with the Wagner unit. There are also spots behind and to the sides of doors that will not accommadate the head that comes with it. You either order the other head or go for one of the other options.

Steam on unpainted paper does NOT need any perforation to work.
You are free to use anything you want and mess up the surface as you wish.