Depends on what the glue is...or was... I removed glue used to glue down tack strips to hold carpeting from my ceramic tile floor by soaking it with white vinegar.....
I wet several layers of paper towel with the vinegar and laid it on the glued down tack strips.....the glue got soft and off it came.

Front or back of the tile? Smooth, textured or rough?

Semi-gloss textured finish.

Goo gone works. Just dab a cloth with a small amount of the goo-gone onto the sticky spot and rub a little bit. Should come right off.

Thank you, I will try it but this glue is 25 years old and it's yellow brown and very hard. The tile is a bit to textured so I can't even get it with a razor blade.

Diamabrush!