It's imperative for you to know How to Purge Crawfish prior to boiling the crawfish. To purge crawfish means to thoroughly clean the live crawfish before you begin to boil them. The following information will provide you with the proper method for purging crawfish.
Even though crawfish are caught in traps that have been placed in the water, crawfish require air to remain alive. They cannot stay submerged in water for a long period of time. If they remain submerged too long, they will die and there will not be any live crawfish to boil.
As you can see in the picture above, the live crawfish are placed in an ice chest to begin the purging process. A large ice chest is ideal to purge crawfish. Many individuals that frequently boil crawfish, also use galvanized and rigid plastic tubs (round and oblong) for this purpose.
"Proper Purging Method"
Dump the live crawfish into your ice chest (make sure the drain is closed).
Note: Do not put your ice chest in the grass. The salt water that you drain from your ice chest may possibly damage your lawn.
Add just enough water to cover the top of the crawfish.
Sprinkle one half of a 26 oz. box of salt on top of the crawfish.
Gently stir the crawfish with a paddle to mix the salt and the water together.
After 5-10 minutes drain the water from the ice chest.
Note: If you do not have a drain in the container that you are using to purge the crawfish, use the crawfish sack to keep the crawfish contained during the draining process.
Fill the ice chest with water once again.
Sprinkle the remaining salt (1/2 box) on top of the crawfish and gently stir.
Discard any crawfish that have already died (the dead crawfish will float to the top).
Note: Under no circumstances should you boil dead crawfish.
After 5-10 minutes drain the water from the ice chest and thoroughly rinse the crawfish.
Make sure that all of the water has drained from your ice chest (simply tilt one end of the ice chest up).
Note: Making sure the crawfish are purged properly is essential to great tasting crawfish.
Remove any grass or debris that you may find in your ice chest.