all #restaurants across the country MUST clean their #hood system periodically or the grease from the cooking builds up so much that it becomes a fire hazard to the restaurant. Thus, fire inspectors throughout the USA and Canada will inspect all commercial kitchen #exhausthood systems to make sure that they are cleaned prior to the grease build up. As long as restaurants cook food, this industry will always exist whether the economy is slow or thriving. Start Your Own Exhaust Hood Cleaning Business!