Removing carpet adhesive from tile is a tedious task that can require repeated treatments before it's successful. Very large jobs might be best left to professionals. Commercial glue-removal products work with varying degrees of success but may contain toxic chemicals. There are nontoxic ways to remove carpet adhesive from tile.
Use a single-edged razor scraper on smaller areas of dried glue on ceramic tile.
Wet a rag with white spirit, spread it on the glue and let it sit for a few minutes. Use a razor or scraper to lift the glue.
Buy a commercial product like Goo Gone, Peel Away 5 or ceramic tile cleaner. Follow the manufacturer's instructions.
Use a heat gun to soften the glue and then scrape it up.
Pour boiling water on the glue to soften it and then scrub it with a stiff wire brush.
Spray WD40 on old glue that has turned black and hardened. The glue will emulsify and can then be scraped up.
Dampen a rag with charcoal lighter fluid. Wipe the glue spots a couple of times. Let it sit for about 30 seconds. Wipe it again with the same rag. Be careful! Lighter fluid is highly flammable, and the fumes can be toxic. Ventilate the room.
Don't use solvent on asphalt tile. Try not to spread glue or solvents into the grout. Wear gloves.