When you are in a park and connected to a sewer outlet, keep the main holding tank dump valve closed, and empty the tank every few days, or whenever it becomes almost full. Only by sending a large volume of liquid, all at once, through the main holding tank will toilet paper and other solids completely wash away. This practice will avoid the accumulation of solids in the main holding tank, which could lead to an unpleasant cleaning job. Should solids accumulate, close the dump valve, fill the tank about half full with water, then tow the trailer for a few miles. The turbulence and surging of the water will usually dissolve the solids into suspension so the tank can be drained.