<Question is: Do I try to get every little piece out that I can; or is this actually a good thing to have in the soil, and I should just till it in???> I see no value in keeping the large unburned pieces in there, only because I doubt they will de-compose in any short length of time. If you have a good tiller, it should be able to bury any ash remnants 6 or 7 inches down. They should be out of harms way. Why take a chance, I guess is my recommendation. Here is the make-up of charcoal, before it gets burned. (percentages are approximate) 10% limestone, just for weight 3% sodium nitrate (to help it light quicker) 4% starch (to help bind everything together) 20% wood (yep, that's it) 65% lignite coal from Canada Jim