What is the ruling on mixing a usurped item with another item whose components are distinguishable?

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If a usurped item is mixed with another item whose components can be distinguished, such as wheat with barley, sesame seeds, large grains with small ones, or black raisins with red ones, the usurper is obligated to separate them and return the original item. The cost of the separator is incumbent upon the usurper. If complete separation is impossible, separation must be performed for all that can be distinguished.