To Remove the Odor of Onions

Fill with cold water kettles and sauce pans in which they have been cooked adding a tablespoonful of bread soda and the same of ammonia. Let stand on the stove until it boils. Then wash in hot suds and rinse well. A pudding or bean pot, treated in this way, will wash easily. Wood ashes in the water will have the same effect.

Source: Things Mother Used To Make, L.M. Gurney