I lever mine off too - it never sticks that badly, so I don't see it as much of a problem. I use sawdust/shavings and like to leave half-burnt fuel in the smoker to ensure an easy re-light next time. Doing this does cause some carbon build-up, mainly in the spout.Common beekeeper problem. I usually flick mine open with a hive tool.
+1 if you leave the smoker with the last of the fire just burn out, it sticks worse.What helps for me is that I always empty my smoker out while it is still hot and never leave it with fuel still inside. Hope this helps. JConnolly is right on the propane torch. Makes lighting the smoker lights easier as well.
I have been using dried grass and pine needles. I usually have to pry at the lid quite a bit to get it freed up. I have scraped it off several times but this only lasts for one fill. I'll have to think on an improvement. I do fabricate and weld Stainless Steel. A torch is relatively simple.
From a fuel side- conifers [pine] are creosote trees as are the needles, dry maybe a bit less than green, but the resins remain after drying. maybe consider semi dry deciduous tree leaves over the dried grass?