If it's sewn in, a seam ripper or in a pinch, a razor blade should make short work of it. If you have little pinholes left in the fabric, you can let them wear out on their own, or just wash the bag - it probably needs it if it was used by someone else.

As for patches, the sky is the limit. If I put on my cynical hat and ironically look into my hipster crystal ball, I see scouting stuff, anything that is from 70's motoring/cb culture, and possibly something corporate, but meaningless without context. I'd suggest avoiding military and police badges you didn't actually earn.