Here is a traditional way of storing milk-caps (based on this link). And below picture of another method, drying (but not milk-caps, other misc forest mushrooms which doesn’t require boiling before use).
Forest mushrooms, part 2
- 100-200g of salt / 1 kg of mushrooms
- 5l of water / 1 kg of mushrooms
- Depending of milk-caps, boil them 10 to 15 minutes.
- Drain the mushrooms in a colander
- Rinse with fresh water and again drain
- Add layers of salt and mushrooms to a glass jar
- Add some weight on the mushrooms and store in a cool place