Skate wing by John Spottiswood.

Skates are delicious, but many people are put off by their bizarre looks. Only the wings are edible. Like their shark relatives, skates have cartilage and tough, sandpapery skin. One way to loosen the skin is to poach them briefly in a mixture of three parts water, one part vinegar. After you peel off the skin, the wing can be further poached, or baked or fried.