Kerosene should be stored for no longer than one to three months. The fuel should not be kept from one season to the next, because it can break down, which leads to inefficient burning.
Kerosene that has gone bad looks cloudy and may contain visible particles. The usability of kerosene can be tested by putting some into a clear jar and allowing it to sit for an hour or more before viewing it. The fuel should be clear with no visible floating material. Kerosene is a by-product of petroleum distillation that is used for heating and cooking in much of the world.