Sent to you by Chris Hunter via Google Reader:
Cast iron skillets are awesome for cooking, but decidedly less awesome to clean. If you're having trouble removing caked on food and grease, some oatmeal can do the trick.
Madhu Shailesh shares this great tip on Snapguide. Once you've used a cast iron scraper to clear the pan of the largest food chunks, sprinkle in some quick oats and a little bit of water. Rubbing the oats around vigorously with your hands will create an oatmeal-like paste that can absorb the leftover grease without stripping the iron. Once you're finished cleaning the pan, try improving it with a flax seed oil seasoning
Clean A Cast Iron Pan in a Very Simple Way | Snapguide