Rinse the blue crabs under cold running water
Discard any dead crabs before cooking
Bring a large pot of salted water to a rolling boil
Add seasoning if desired, such as Old Bay or crab boil seasoning
Place a steaming rack in the pot or use a steamer basket
Add the crabs to the steamer basket or directly into the boiling water
Cover the pot tightly
Steam live blue crabs for about 20 to 25 minutes
Boil live blue crabs for about 10 to 15 minutes
Cook until the shells turn bright red or orange
Remove the crabs with tongs
Let the crabs cool slightly before handling
Serve with melted butter, vinegar, or lemon if desired