You can try sanding with 100 grit sandpaper or you can use klean strip adhesive remover but neither of these methods is guaranteed to easily produce satisfactory results.
Remove glue from wall tile.
Look for a formula that is either made for ceramic tile.
If the adhesive used was organic mastic the water will begin to soften it allowing you to.
You can take some form of scalpel to help with the initial removal of the glue.
If any adhesive gets stuck to the brush.
Simply point the nozzle towards the glue and spray as needed.
The second step is to remove the adhesive or tile glue which held the tile in place.
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.
To scrape or soak that is the question.
You will begin to notice that the glue becomes a lot easier to remove.
Allow time for the solvent to work into the glue.
Just answered your thread about repairing walls after removing wallpaper but i would recommend a completely different approach for the walls in this photo.
Removing thin set mortar thin set mortar is actually a cement product that is used on the floor as well as on the wall tiles in many of the areas.
Pour a small amount of adhesive removing solvent over any remaining residue that is left behind once you remove the adhesive.
Removing wall tile glue accept the inevitable.
How to remove tile glue the first step is to remove the tile itself whether it be cut or chiseled from the surface it is attached to.
Scrub the solvent into the residue with a scouring pad.
Scrape the surface of the adhesive with a stiff bristle brush.
Heat the surface of the adhesive with the heat gun.
Wait several minutes and use a large scrapper to remove the mastic.
Apply an adhesive removing paste to the wall.
How to remove tile adhesive from drywall.
Work in 2 foot square sections to prevent the adhesive from hardening as you work.
This will not only soften the adhesive but it will begin to gently lift it from the surface of your ceramic tiles.
Apply some water to a small section of the adhesive.
Scrape as much adhesive off as possible using a big blade scraper the ones.
Mastic and other tile adhesives are formulated.
The different options for removing glue residue are shown below.
How to remove ceramic tile glue from a wall.