Cooked crabs that are not finished are usually not recommended by doctors for a second meal.
But river crabs are so expensive that it's a real shame to throw them away. The best way to preserve overnight crabs is to cook them, let them cool, wrap them in plastic wrap and put them in the freezer.
Eating again, not later than noon of the next day, and to heat the raw crab and steam through the same fire, so as not to waste the basis of as much as possible to ensure the safety of consumption.