Unless it's special tile adhesive designed for constant submersion just
leave the tiles in a bucket of water for a few days and it should then
just rub off with a cloth. You will have to let the tiles dry before
reusing them though or they won't stick properly.

If that doesn't work you could try a surform or some thing like that but
you would need to be careful that you don't chip the edges of the tile.

Graham

Jen wrote:
Hi, my husband has given me the awful job of taken off the tile adhesive
from the back of ceramic tiles. He's taken the tiles off the bathroom wall,
and wants to reuse them. He's updating the bathroom so thankfully it's only
about 40 tiles. Any ideas what's the quickest solution to this dreaded task?
I would be grateful for your advise

Jen