Many old books cover the care of antiques. They sometimes give false information because the products suggested have changed. Ivory Snow was once a pure soap recommended for washing vintage fabrics. It was reformulated in 1993 and is now a detergent, not safe for all fabrics.
Copper pans must have tinned interiors to be safe to use for cooking. Always use a wooden spoon. Always have some liquid in the pan when you start cooking. Don’t scour the pan; it will damage the layer of tin and expose some copper. To clean up after using the pan, soak it in water, then dry it with a soft cloth.