To repair chips in crystal glass, start by taping a small piece of coarse sandpaper onto the eraser of a pencil. Wet a soft cloth with water, and wipe the chipped area of the glass to help reduce friction while sanding. Using the pencil, sand the edge of any chipped sections on the glass until they are smooth.
Switch the coarse sandpaper with a medium-grit sandpaper, and repeat the process of sanding the chipped area. Sand again with a fine-grit sandpaper. Sanding makes the surface of the glass smooth enough to use without causing harm. Use the wet cloth to wipe the chipped area clean of any glass dust.
If the chipped area is small, the glass should now be usable. If the glass is chipped into pieces, apply a glass cement or epoxy to the smoothed sections, and press the pieces together. Tape the sections together to hold them in place as they dry. Consult the manufacturer's directions concerning the length of time the epoxy or cement needs to dry.
Because the crystal glass is likely to hold fluid, use an epoxy or cement that can be used for food or beverage glass repair. Always use a mask, and work in a ventilated area when sanding and applying epoxy or cement. Sanding glass or crystal produces dust that is harmful if inhaled, and cement and epoxy produce strong fumes.