I soak them with goo gone for a few minutes and then work some dental floss behind it to remove. Did this with the 335i for a dealer badge that had been on there for 3 years. Came right off.
That is a good tip. I'll have to try that next time.
As for just spot treating, I would soak the affected areas with WW, let it sit for about 10-15 minutes, and the bugs should come off fairly easily.