The best way to reheat crabs is to steam them for 5 to 10 minutes until their centers are hot. Crack open a claw after 5 minutes and each minute thereafter until they're piping hot. There is no appreciable loss of quality from re-steaming. Although we season our steamed crabs, adding more seasoning to them will ensure that your re-steaming experience is memorable. Keep in mind that steamed crabs are already cooked. Steaming longer than 10 minutes will cause the meat to toughen and dry out. You may also reheat crabs in the microwave by placing a damp paper towel over them and cooking on high for 1 to 2 minutes. Or warm them in the oven at 375 degrees for approximately 10 minutes.