I use a heat gun to soften them and then you should be able to peel them off. Be careful, do not use a metal scraper to remove them. Once the main part is off you will need to remove the old adhesive. Paint remover works for that, then use a strong solvent for the final cleaning. And in case you don't know this trick, here is how to apply the new onw. First do not do it outside on a windy day. Peel the paper backing off the new decal, then spray the sticky part AND the vac with window cleaner. Then put the decal on and you will have about an hour to squeeze out the air bubbles and wrinkles. After a couple of hours the cleaner evaporates and you're done. If you want to really do it right polish the vac or use a 50/50 solution of wall cleaner and water.