Walls and Ceilings - Removing tile mastic on plaster wall?

The previous owners of my house went tile crazy in the kitchen, and I want to remove most of the tile and simply paint the walls. Of course, there is hardened mastic underneath all the tile, and I'm wondering if there is any reliable way of removing the mastic and returning the wall to an even appearance? The tile/mastic is over plaster not drywall, by the way, and so I am hoping to avoid the difficult and nasty job of tearing down all the plaster!!

Thanks,
Don

Are you sure that the tile are stuck with mastic and not mortar? If so some of about three things could happen.
1. You could use a sharp chisel or knife and scrape it right off. If the walls had been painted it might come off easily or take only paint with it.
2. You could use a sharp chisel of knife and scrape it off but take some of the plaster finish with it. This isn't too bad you can use a coat or two of quickset joint compound and fill the holes snd, prime and paint.
3. You could use something more aggressive and heavier to take it off. It could take the finish and some of the brown coat with it. If there is anything left you can still patch it as above.
Most likely is that all of the above will happen to some degree. Patch it as needed with quickset joint mud.
Now you might be able to use heat to soften the mastic and make it a little easier to remove with less wall damage. Be careful the mastic might be quite flamable.
Don't be afraid to experiment. You will figure out what is best for removal. Then if you have questions about repair ask again with specifics and we can help you.
Good luck. Let us know how it goes.

If it is mastic, try spraying it with some water, try to get it as wet as you can and then use the scraper as mentioned above. The mastics wetre reformulated several years ago and now tend to soften up when they get wet so it may make the scraping a lot easier. That is also the reason I dont promote the use of mastic for tile in wet areas.

Thanks guys. Heat seemed to do the trick. It came off pretty quickly and with little damage to the plaster. But if anyone is reading this and thinking about trying to use heat, heed tightcoat's advice and be very careful. The mastic lights up quickly. The approach that worked the best for me was to give a blast of heat (3-4 secs) to about a 4" square area, remove the heat, scrape -- making sure the remove all the loose material, as this is the stuff that will light up most quickly. Obviously some good heat-resistant gloves are essential.