Sean, what an ucky bummer!!!! Go for burlap, I have used my smoker for over 2 years and haven't had to clean any crap out of it yet. It just plain and simply does not have build up junk in it.
I have been using the dryed staghorn sumac flowers for smoke, along with burlap. I surely hope that the sumac makes creosote. Time will be the teller of that tale though. I find these two combined burn for a long, long time. I had it going for over an hour the other day when I was outside looking into all the 9 (Yeah) colonies that I have. I didn't use very much smoke with them at all, but I just kept it smoldering around, just in case. I now take a little spray bottle of sugar syrup, very diluted, and give the bees a little tiny bit of this misted on them. They seem to really like it (of course), not enough that it would even make them wet, but it seemed to keep them busy enough. No stings, just quiet little girls doing their own thing, and never minding this giant that opened up their little home. I use baby powder on my hands always too, they seem to also not mind this, maybe they like it, I don't know. A fellow from the bee club that came to my house my first year of beekeeping to help me catch a swarm told me to use baby powder cause the bees like it. Always worked for me. I have never once had a sting to my hand while working the colonies, and I never, ever wear gloves.
When I was inserting the sticky boards the other day for the varroa mite I put on gloves because I knew my hands were going to be interferring a little with the flight of the bees coming and going. But it was about 5 seconds after I began that I removed the gloves. What a nuisance. Put on the baby powder and away I went.
Have a wonderful day, I think that you are gonna have to buy a new smoker, that is too bad. Beautiful life, great health. Cindi