Removing the graphics on your van it is a fairly easy task. Vinyl or plastic graphics are usually stuck to vehicles with glue or another adhesive. If the graphics were painted on, removing them might take more time so you don't damage the underlayer of paint. Using caution is important in either case so that you don't hurt the finish, which could require costly repairs to make it shiny and new again.
Peel off any graphics that have loose edges. Use a plastic scraper if the graphics don't peel off easily. Be careful not to damage the paint job.
Use a heat gun or blow dryer to loosen the adhesive of stubborn graphics. Adhesive might remain after you remove the images, so you might need to use the heat gun or blow dryer again to help get it off. Once you've loosened it, wipe off the adhesive with a rag.
Use adhesive remover, which you can find at auto or hardware stores, to remove any residue. Soak a rag in a small amount of the adhesive remover and rub until the adhesive is gone.
Spray a small amount of oven cleaner on a rag to remove painted graphics. Try this on a small area first to be sure that it doesn't hurt the van's paint.
Wash the van using auto soap, sponges and water to remove any traces and to leave the van sparkling clean.