TIME TAKEN 
20-30 MINUTES if you do them by hand
20-30 MINUTES if you do them by handIf you roll with a gurney USE THAT INSTEAD, if you don't make sure you spray these grates with SHYN degreaser, on every part of them, don't spot spray, trust me you'll be there for an hour.
Hot tip - As you brush them out make sure the hot water is running over them as your brushing out the grime with your SLIM LINE DETAILING BRUSH 
