FlipFuel Fuel Transfer Device
Brought to you by backpackers to solve a simple problem. What do I do with this box of partial fuel containers I won't take on a trip? Now you can easily consolidate your backpacking fuel & recycle the empty fuel canisters.
Gear for Adventure has tested these, and they work great! Just put one in the sun and one in the freezer for 5 minutes, the pressure differential pushes fuel from the warm one into the cold one. It's easy!