What is the best way to remove old stick-on type pinstripes from the paint?
If there is clear-coat type of paint over them, then there is really no way that’s reasonable at home. If not, use a heat gun or a hair dryer to soften the adhesive and then slowly peel it away. Remove the remaining adhesive residue with any of the available release solvents such as Goo Gone. Be sure to thoroughly rinse the area when you’re done.