Wash the bumper with soap and water
Dry the area completely
Warm the sticker with a hair dryer or heat gun on low
Lift an edge with a plastic scraper or credit card
Peel the sticker off slowly
Reheat stubborn sections as needed
Apply adhesive remover or rubbing alcohol to leftover residue
Let it sit briefly
Wipe the residue away with a microfiber cloth
Repeat until the surface is clean
Wash the bumper again
Dry the bumper completely