Thanks to all for responding to my smokebox innards question. You may suppose that I will have a request for further and better particulars soon but now for another wally question. I've been pondering, I really should get out more, on clinker. I run my locos. They steam well to start with. I poke the fire about a bit. I throw out the really manky bits of coal before firing them. The pressure is more and more reluctant to come up. I drop the fire and find loads of clinker. Two questions. First when I look at the the fire or rake it how do I spot the clinker? Second question what do I do save for pull it out, if I can recognise it amongst the other white hot bits when I find some? MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.