Flooring Tile - Removing old tile

Is there anyway to remove old premixed mastic from a wall without having to rip out he drywall? There is no backer board behind this area. it is only 24" x24" and I'd hate to have to take out the drywall.
I though maybe a heat gun would soften the mastic enought to scrape it off.
Any thoughts would be appreciated.

For the amount of work and the possible damage to the surface, i'd just replace the rock. If you use a fast setting type joint compound like Durabond, you could cut it out install the new rock, give it a tape the joints (coat 1) second coat later that day (coat 2) and third and final coat later on. As a matter of fact, you could do it this weekend when you watch Atlanta get creamed by Philly, and time it like this-cut out/replace and do your first coat and tape before the game starts, second coat at half time while dancing about from the Eagles lead, and third coat after the game is over and Atlanta is moping on the way to Philadelphia International Airport. :D :thumbup: :D

Now that the Pack is done, I'm a short term Eagles fan.
Thanks for the info, much to my dismay. I just hope there are studs behind the rock.

NO worry on that. Just take a 1x3 and screw it to the edge of the hole so that 1/2 of it is behind the remaining sheet rock and it will provide an area to screw the new sheet rock.