The normal method to remove the black film is: divide the raw beef venetian blinds into 5 pieces, put it into a bucket, pour boiling water, stir it with a wooden stick for 3 minutes, take it out and put it on a chopping board, rub off the black film on it hard, rinse it with clear water, put it in a cold water pot and cook it for 1 hour until it is 70% rotten, and then take it out. At this point, they are considered processed.
Nowadays, many unscrupulous businessmen use hydrogen peroxide to make beef venetian blinds white, crisp and not mottled, which is very harmful to human health.