I just finished a smoke yesterday and today when I cleaning my MES 30 Gen 1 I looked at all the carbon buildup inside. It was really hardened around the door frame, on the walls, the ceiling, the wood chip loader, everywhere. I don't like to do heavy duty interior cleaning (I do take out the racks, water bowl and drip pan to hand wash those and I wipe out the grease tray) because I don't want to use detergent or other chemical cleaners inside. Well, as it happens my wife and I are big fans of Pampered Chef products. One or our favorite little tools is a square hard plastic scraper that they sell. Don't know what took me so long to think of it but today I took that scraper and easily scraped off all the carbon build up that I chose to get rid of. Even used it on the rack guides on the wall and up inside the top vent. Tons and tons of carbon fell to the floor of the smoker and I easily brushed them all out. And for good measure I cleaned off the rear sensors, using a Pampered Chef cleaning brush to clean out the notches on the hi temp cutoff switch (the dime-shaped thing).
Now, if you look at the smokers used by pros and restaurants that you see on TV, none of them are cleaned. They're all stained and they also have various degrees of carbon buildup. My point is I that I cleaned out my smoker interior while retaining its original seasoning. If the pros don't feel it's important to keep their smokers looking shiny, brand-spankin' new then I have no need to keep mine looking factory fresh, either. In fact, having my MES look well-used is a source of pride. Just to clarify, we're not Pampered Chef distributors or whatever they're called. I'm sure any scraping tool will work. But it was impressive how easily all that stuff came off. Now I once again have good door seals and I don't have to deal with carbon deposits falling on the food if I accidentally rub my arm against the ceiling. To finish up the cleaning I wiped the interior (and selected spots on the exterior) down with damp paper towels and let the whole thing dry.
I'm sure many of you have your own favorite ways to clean your MES but I just wanted to share mine. Hope this helps.