I've done exactly one long-ish smoke with the smoke generator using cherry pellets. After it was done and cooled there's a ton of sticky creosote inside the generator and on the smoker cabinet. What's the best way to clean that off?
Hot water and soap or try oven cleaner. I used oven cleaner on the inside of my smoker once when field mice set up home. Clean as a whistle and no damage.
You could try some Simple Green or Super Clean. A soak in good strong solution of one of them followed by a little brush work and a good rinsing with water. Both are excellent cleaner/degreasers.