Dear members: I believe that 90% of maintenance and preventative maintenance is :doing the dishes". In other words, keeping things clean and lubricated. I concur that cleaning the foil is important. BUT... As an opposing opinion regarding the following statement: "I would clean the foil with a small very stiff brush, possibly stainless "

I would STRONGLY advise against using any kind of metal brush on any anodized aluminum object (i.e. the foil). This ill scratch the thin, but hard, anodized surface treatment and will lead to corrosion of the aluminum structure.

If you need to clean the foil, use soap and hot water and a bristle brush made of nylon or other synthetic bristles. If you can clean it up using a good rag, soap and water without resorting to any kind of brush it would be best. If accretions of material warrant stronger methods consider something like acetone to remove layers of oil, grease, or wax.

Just my experience with anodized aircraft structures.

Gary Silver
s/v Liahona