How do you use Level Gauge Cleaner?

To clean gauges, choose a warm day, above 75F, pour 1/2 of bottle of LGC into 40 gallon black holding tank through toilet opening. Pour 1/2 of bottle of LGC into 40 gallon grey holding tank through sink or shower drain. Flush the drain with running water and fill the tank. Mix by driving around and let it sit 24 hours. Drive vehicle again to loosen deposits. Empty and rinse holding tank. Product’s effectiveness doubles between 75 and 85 F. DO NOT use in freshwater tank.