When turning the spigot to the off position, do not move it beyond 180 degrees or parallel with the edge of the cube. Pushing the handle beyond this point (so that the edge of the handle touches the cube) may actually open its internal valve slightly, thus causing a small drip. The spigots are quite durable, and they can be used many times over. They can be washed with warm water to remove residue as needed.
A number of darkroom technicians have told us that they suspend plastic cups with string, like a bucket and handle, beneath the nozzle of the spigot to catch drips when needed.