Scrape the surface of the adhesive with a stiff bristle brush.
How to remove old tile adhesive from plaster wall.
If the adhesive used was organic mastic the water will begin to soften it allowing you to.
If the adhesive is not cement based you could try sprinkling water to the wall to ease the scrapping process.
You will then have to pry off the leftover residue.
Look for a formula that is either made for ceramic tile.
I have started by removing the tiles from the walls but the plasterboard is now a mess with patches lumps of tile adhesive still stuck to it.
This can be accomplished using a pry bar to peel off the larger chunks.
All the the tiles have been removed by bolster chisel and as you will all know the bare plasterboard is now a mess and i need it to be clean before i can start putting the new tiles up.
Apply some water to a small section of the adhesive.
Step 3 wipe some tile adhesive remover over the surface of the wall.
Wait several minutes and use a large scrapper to remove the mastic.
Irrespective of the adhesive formula you have to cover the floor with old cloths as to protect it from the residues which will fall off the wall.
Apply an adhesive removing paste to the wall.
If any adhesive gets stuck to the brush remove it by hand and continue until no more adhesive remains on the wall.