Every other year I vacuum out the combustion chamber on our Camray 5. It must be getting on for 20 years old so it isn't new by a long shot. But it seems to work. One thing I noticed today is that the ash appears to have a lot of iron in it. Is this normal? I appreciate that water is one of the products of combustion and the chamber is iron but is this much rust normal? If not, what could be the cause? At a rental property I own I had an oil engineer out to service the boiler (a Heatslave) and the debris was like a light brown, sort of like expanding foam.