Mod Podge is an all-purpose crafting adhesive. It is commonly used in decoupage projects because it is easy to apply, will not make the paper wrinkle, and dries clear. Once the adhesive is dry, however, it will not simply wipe off. You can remove it from glass by rehydrating the glue with water. If the glue is too old for rehydration, or too thickly applied, a mineral spirits application will remove it.
Fill a spray bottle with water. Spray it on the glass until it is completely covered with water. If the glass is a dish or other portable object, fill a sink with water and submerge the dish in the water.
Leave the glass to soak for 30 minutes. If it begins to dry out in that time, spray it again.
Wipe the glass with a dry towel to remove the re-hydrated Mod Podge. If it still will not come off, moisten the towel with mineral spirits and gently scrub the glue until it is removed.