I find the easiest way to frag them is to put a piece of rubble rock right near they body and within a few days, the cesp will start to move a piece of its body over, then you grab a razor blade and slice it. A piece of its body will be on the rubble rock and in a few more days will develop into another cesp.
They are not as rare in some areas and rare in other areas. I see pom pom xenia still sell for 19-30 so I'd imagine one day even if cesps become common, they wouldn't be dirt cheap.