We've gone thru 2 Insinkerator Evolution units in the past 8 years. Prior to that, the disposal was not an Insinkerator & we had it for 20+ years without any smell problems. We thought we would go to the Insinkerator (known for good quality & performance) at the same time we replaced the sink 8 years ago. It was fine in the beginning, but after a while we started having the smell. We've had more than one plumber work on the problem, trying to get rid of the smell, but without any luck. That's when we replaced the unit (twice) with a new one. The new unit was OK for a while, but now the smell is back. Any ideas???????