Old post but just what I needed as a new smoker user! Cleaned mine out after smoking yesterday and left them in there figuring I would check these forums.
Likely will go the method of taking them out of my 18.5 in order to clean the ashes out of the bottom before my next smoke.
Glad to see this topic as I am attempting the same today. Plan on filling some water in as I have seen from others how the first few smokes run a bit hot.