About once a year the exhaust hood needs the intake air filters cleaned. The filters (2 of them) are on the roof and can be accessed through removing two screws on top of the intake unit.
Here are some pictures after I already removed the two filters for cleaning. I generally just spray the filters out real well with water sprayer at kitchen sink. Maybe if they are real bad you can let them soak for awhile in the 3-sink in the kitchen then spray the filters out and let them run a couple of time in the automatic dishwasher.
Takes two screws to remove the top and to get to the filters to slide them out.
Here is the exhaust fan unit for the actual "exhaust". The belt, pictured below, can be bought at Grainger in town on Jordan Lane. (click the link) The belts are not that expensive so we just get them there. There may be other places you can purchase them. Always buy at least 2 at a time so there is always a backup. You can use a socket set or some hand wrenches to loosen and tighten the bolts in order to put another belt on BUT if the belt has already broken off I usually put the new belt all the way on the motor pulley and partially on the fan pulley and give it a quick spin and the belt will pop all the way on like a tight bicycle tire without ever having to use any tools.
Both the intake and exhaust unit have seperate electrical switches close to their motors so you don't have to turn the exhaust switch off in the kitchen to work on them. Just climb the ladder to the roof and switch off the one you want to work on.
Both Pastor Will Umbarger and Jim Cochran have some experience with this maintenance job so if you have any questions they should be able to help you out!