Place a piece of ice on the area to harden the gum. Secondly, pull off the gum from the seat or use a blunt scraper to scrape it off gently. Next, spray WD-40 on the remaining area and scrape it off again. After that, spray upholstery cleaner on the car seat and then scrub using a soft cloth towel. Finally, wet a sponge with some warm water and then let the seat to dry.