What do you do when there’s a mechanical problem occurs after you clean it? We cleaned an exhaust system that was way overdue for cleaning and by the looks of , it had not been cleaned properly in a very long time. Needless to say the fan was weighed down with lots of grease. When we were done cleaning it and turn it on it was vibrating so bad that felt it all thru out the building. After close inspection we noticed that it had a couple bolts missing and some loose ones has well. We fixed it and it was fine when we left, but then it did it again. I don’t feel this is our responsibility, all we did was clean it and were not negligent in any way. It’s my opinion that the problem was there all along, but because the fan was so weighed down with grease it kept quiet. Any advice is so appreciated.