For those stuck with a carboned-up non-aluminum pan or grill and no immediate access to TKO, I believe soaking the affected areas in household ammonia will remove/loosen the deposits (credit for the tip to Graham Haley). When done, throw the carbon/ammonia combination on the compost pile. With grills, one would need a container of some sort to do the immersion.
Here's a tip for cleaning grills that I found on the web (preferably for organic lawns

)
+++
From
http://www.askyourneighbor.com/hhints.htm
"CLEAN THE GRILL
This cleanup trick works while you sleep! Lay a barbecue grill rack on the lawn overnight-the dew will combine with the enzymes in the grass to loosen any burned-on grease. Try it with messy oven racks too!"
+++
Totally off topic is the technique for using a molasses bath to remove rust from iron/steel, as described in this exchange concerning steam engine restoration:
http://www.steamengine.com.au/ic/faq/mollasis.html