May well be water soluble.
http://www.humboldt1.com/~dspreen/bo...ges/12966.html

"traderfjp" wrote in message
oups.com...
How difficult is it to remove ceramic tile from Cememt board? I used
Mastic for adhesive? Will I be able to remove the tiles without
destroying the cement board? Will I be able to re-use the cement
board? Thanks in advance