Operators of the Archimedes Particle Metrology System are frequent users of the fluidics feature known as the “Sneeze”. Most commonly it is activated as part of maintaining a clog-free microfluidic system. What exactly is happening during a sneeze is not well understood. Furthermore, the graphical display occurring during a sneeze can be misleading. In this technical note, we explain the mechanics of the Sneeze. We present a variety of scenarios and their resulting graphical output to illustrate and explain what is happening within the sensor and microfluidic system.