Really basic brush question

Forgive me if this sounds stupid, but I've been wondering for a while. When I use a carbon fiber brush on records, I hold the brush in a line from the center of the record to the periphery and turn the record underneath it. Eventually there is a line of dust extending radially on the record. Now here's the question: When you're done brushing, how do you get this line of dust off? Do you simply brush it off to the outside of the record? Or perhaps go after it with a damp cloth?

Thanks in advance for trying to clear up (what should be) a really basic question.