I bought a DIY'er (low budget) duplex and on the one side in the kitchen/dining they had installed 5/8 drywall (about 20 full sheets plus), vertical (8' high) and taped/compounded the seams and screws.

Here's the issue - they installed it over the old lath boards (plaster was removed) but didn't bother putting insulation in the walls or updating the wiring (bx cable with cloth covered wires). Plus to top it off, the room has a 9ft ceiling - they planned to used a dropped acoustic tile ceiling which i do not like...

Is there any way to save these sheets for re-use?
Thanks

 

Not that I've seen - removing them from the walls usually destroys them.

I'd replace them with 1/2" thick 54" wide drywall hung horizontally.

 

To add to Mitch's comments, even if you did get it off, it would probably be such a mess that it would cost twice as much to finish it.

54" wide drywall hung horizontally is a must. Where I live it only comes in 12' lengths.