I like a coffee when I'm out and about for a relaxing way to pass the time. What's the best way to avoid bringing a kettle. I know everyone has "Crusader Cup" ready to cut and paste but I'm thinking for small groups where you want to make for more than one and want to boil water in something you can pour from but everyone else has plastic cups. Or is a Trangia kettle thats small and squat the most economical space saver. (Should add I'm thinking for over an open fire)