Put your mushrooms into salt and water, and wash them clean with a flannel, throw them into water as you do them; then boil some salt and water: when it boils, put in your mushrooms, and let them boil one minute. Take them out, and smother them between two flannels; when cold, put them into white wine vinegar, with what spice you choose. The vinegar must be boiled and stand till cold. Keep them closely tied down with a bladder. A bit of alum is frequently put to keep them firm.
The white mushrooms are done the same way, using milk and water instead of salt and water, distilled vinegar in the room of white wine vinegar, no spices except mace, and a lump of alum.