Steer clear of using cleaning agents. The chemicals in cleaning agents can disrupt natural bacterias present in the trap. This bacteria is vital to the functioning of the grease trap in that they help to eat away the grease. Also, you should never use hot water or de-greasers to clean the grease trap. These will melt the grease, allowing it to enter the sewage system. The trap should always be cleaned with cold running water.
Just keep these pointers in mind and you won't have to worry about harming the functioning of your grease trap while cleaning it.
Zurn Grease Traps can be found at www.supplyhouse.com.