On Thu, 10 May 2007 00:04:31 +0100, Philip K
wrote:

Our quite old, but regularly serviced, Aga has recently sooted up the
complete inside of the lid of the hot (left hand) hotplate. There are
also black soot marks around the ring at the outside of the plate.

The Aga is oil fired.

Thanks to all who responded (especially those who made the point about
possible safety concerns due to Carbon Monoxide).

In the event, the Aga went out before I could switch it off! We had it
serviced and the technician showed my wife where there had been a
problem with the oil feed pipe at the base of the Aga - the connecting
joint was bad and there had been a leak of fuel. He replaced the worn
part with a new one and it's working fine now.