I don't have any tool that I use for that area and I'm not aware of one out there. Those areas can be tough to clean and I don't think there is a tool for it because of the risk to scratch the paint on the surrounding area while putting a brush in there. I usually force a microfiber towel in there and it usually gets it out no problem. Sometimes I have to really work the towel into that area to get it in there. Other than that I don't really have any special tips or products. Maybe someone else here on the board has been able to solve this problem.
Greg @ Detailed Image