Grease Interceptors should be completely pumped (i.e., dry-pumped removing the grease mat, liquids, sludge, and wash down material from the interior walls). Grease Traps should be completely pumped (i.e., dry-pumped removing the grease mat, liquids, and solids from walls, screens, baffles and air-relief chambers). Can you recommend a maintenance schedule? All grease interceptors should be cleaned at least every 3 months, but some establishments may find it necessary to clean their traps more often. If the establishment has to clean its trap too often, the owner should consider installing a larger trap or interceptor.