No matter what comes into contact with air, it will not be preserved well, and it will be oxidized after a long time.

Any of the above pens will do. If you want to keep it for a long time, you can use a glass photo frame (buy another bottle of Spray Fixative for art) or plastic packaging (some plastic packaging can be typed and copied, and covered with a plastic film).

Don't let it touch the air or be exposed to the sun.