A different fave of prepping blue crabs is always to dunk them in a bucket of ice water for around 5 - 10 minutes. It puts them to sleep and anesthetizes them. We use rubber gloves to rip off the backs and it kills them promptly. Take away and serve: https://brooksmxgqv.livebloggs.com/38121824/the-smart-trick-of-frozen-crabs-near-me-that-no-one-is-discussing