Eye dropper was my go to, but also in cool weather you can just open the valve and hold the tank between your hands to warm the fuel. Just has to be warmer than the surrounding air to create enough pressure to force fuel out and into the cup. Some of my caver friends (don't look at the black on the bottom of my tank, OK?) would heat the tank with a zippo (or campfire) to force fuel into the cup. Or, just open the valve and blow into the tank, stopping when you feel the fuel run down your cheek. Most spectacular at night of course.