any tips on what gets buffing compound out of unwanted places without hurting paint?

 

I've saved an old tooth brush in my tool box for things like that.

 

and if it doesn't get it all because it's too dry and caked on, then spray the white stuff with a 3 min quick detailer product. Also this works great for getting the white residue off the part number codes on the plastic in brake lights etc. Once you get rid of all that white stuff resolve to never use wax base products or buffer polishing compounds again on your toy.
Great shines can be had without risking buffer damage to your paint by starting with a clay bar application, followed by a polish that comes in several strengths (all hand applied and buffed), then followed by applying a resin/acrylic gLaze. This whole process takes about 2 hours to do on a Vette and none of the steps require hard rubbing or working up a sweat to complete! Your shiney finish will be good for at least 6 months with this & all you need is a 3 min quick detailer spray for touch ups when you want to get a "just polished" look. The "wet look" products result in an especially deep shine.
I personally will not use wax base products. They are soft and every hand that touches your car leaves an impression. That will not happen with non-wax based products. Most all of the resin/acrylic based products will not leave any white residue.
There are several vendors at this CF link that sell the procducts I am describing and some even have videos demonstrating what I posted.
http://forums.corvetteforum.com/car-care-discussion-10/