Grease traps are designed to trap fatty oils, greases, and sludge, and to separate the oils from the water. These substances pass through a catching system that gives them the time to cool off and solidify. Below are some reasons why routine grease trap cleaning is essential: Grease traps should be maintained to work effectively in keeping your grease trap clean. NFPA-96 Standard requires that these traps remain clutter-free and functional. Failure to comply with the standard can cause a problem for your business. Grease trap cleaning should be done every 90 days or less for best results. This will minimize foul odors emanating from the trap.