You might just be able to use your thumb or a large drafter's eraser. They sell a rotary eraser for shops. If it is factory paint, it is tougher and more cured than aftermarket paint jobs, so try mild thinner such as just turpentine, house painters thinner. Lacquer or acetone thinner is too harsh so do not leave it on for more than a couple seconds. Even brake fluid can eat through some auto paint if it sits there for an hour. The automotive paint shops sell a highly volatile cleaner that does this for standard body side molding rubber glues, but it is expensive. If it very well stuck it may have been put on with a cyanoacrylate glue which is a nightmare. Too much heat will soften everything and even factory paint will come off.