What is the ruling on selling a Ribawi item mixed with a substantial, non-purposeful admixture?

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If the admixture is substantial and not for the purpose of the intended item, such as milk mixed with water or adulterated coinage, the sale of one such item for another like it is impermissible. This is because the mixing is not for its purpose and it corrupts the intended parity. If one sells adulterated silver coinage for dirhams (a non-intended component), a possibility for permissibility exists because it is being sold for an item lacking the intended component, resembling the sale of milk for a sheep that contains milk. Conversely, prohibiting it is possible based on the alternate view in the fundamental rulings.