I have a cast iron Dutch oven that I use for chili, stew, etc. Yesterday I made a pot of beef stew and it was wonderful although some of it stuck to the bottom of the Dutch oven. Needless to say, I didn't scrape the bottom when I was serving the stew and it never smelled scorched, however, when I began cleaning it and scraping what had been stuck on the bottom, the stench became very apparent. I let it soak overnight before trying to clean it, in hopes that it would loosen it up, which it did, but now that I've hand washed and dried it, there is still some black stuff stuck on the bottom that I cannot get to come off and it still wreaks! Any suggestions for cleaning my Dutch oven?