If the Mod Podge is still wet, rinse it out with warm water and rub it with dish soap or laundry detergent. If it’s dried, scrape off what you can, then soak the fabric in warm water to soften it before scrubbing with detergent. For stubborn residue, use a little white vinegar or rubbing alcohol (test first). Don’t put the clothing in the dryer until the stain is completely gone.
