Alan, I LOVE the AeroPress. Its simple design is a work of art, I love how everything works together to allow multiple ways to brew. I commend you on your brilliant design. Rather than a question I have a suggestion. On the bottom of the filter holder inside the hexagon add notches the size of the filter cap so the user can use it as a "key" when the cap gets screwed on a little tight. I have severe tendon damage in my hand and sometimes getting the cap off and on can be hard. This subtle design change would make the AeroPress more accessible to people with arthritis as well. – From Stuart H.

Thank you for your comments and question. I am very pleased that you enjoy your AeroPress so much. Please try not fastening the filter cap so tightly in the first place. You'll discover that the AeroPress works fine without tightly attaching the cap. You might also try a simple rubber sheet which is sold for removing jar caps. It's surprisingly helpful.