Why not use a pencil or record the conversation with your phone then play it back instead of pens. You could place different brands/types in the freezer to test too. I keep a blanket in my car this could help in your case too. You never know if someone else might need it. Even though I do not plan on walking miles in the cold, I always dress as if I am. Again, never know when you will have to. I remove layers once I get to my destination if necessary.