Melt margarine in large saucepan. Add celery, cook 3 minutes.Add flour and stir over low heat until frothy. Cook additional 3 minutes, stirring often.Add hot pepper sauce. Gradually stir in milk. Increase heat and bring to a boil, then reduce heat to simmer. Allow to simmer and thicken 10 minutes.Add crab meat and scallions. Taste with salt. Serve immediately.
Put all the ingredients in a large pot and bring to boil. Reduce the heat and simmer gently for 30 minutes. Remove the stock from the heat. Strain the mixture through a fine sieve. Return the liquid to the stove and simmer until the liquid is reduced by half. Let the stock cool down, then refrigerate or freeze.