wash the whole bullwhip, cut off the outer skin, then scald it with boiling water, take it out and tear off the outer skin, remove the fat and tendon around the bullwhip, then cut off the blood line from the middle with scissors, and you can see the urethra after cutting off the bullwhip. This is why the bullwhip smells so bad. Carefully remove this part with a knife, and then chop off the head of the bullwhip.