Removing glue from chips is not an easy chore and you are not always going to be successful. If the glue is into the surface of the chip, then removing the glue will also remove some clay. The glue may also have discolored the chip.

I would start with soaking the chip in water for a couple of days to soften the glue, unless you think that the soaking would cause damage. If that does not work, you can try freezing the chip to see if the glue will harden to the point that it will crack off easily. The final suggestion is to get a hobby knife with a thin sharp edge. Try to pick the glue off the surface of the chip, without touching the chip. It is very difficult to do and you can wind up damaging the chip if the knife touches the chip, but it does work if you are very careful.