Decided to have a look at my air filters to see if they needed replacement. I think they were replaced a year ago. To my surprise they did not. They looked brand new. I dusted them off a little anyway. The inside of the air box covers were squeeky clean too! But then I checked the interior of the bottom half of airbox and found it was dirty. I don't think the service folks bothered to look or clean the inside. So I went ahead and cleaned everything. Total time for disassembly cleaning and re-assembly about 15 minutes.
Bear in mind the bottom part of the air box is the "dirty" side so it's not unusual for a certain amount of debris to accumulate in there.