| You may find also :-
water deposits (from condensation, or internal leak,ie head gasket)
White metal from your main bearings
silica deposits...from sand left in the castings of the crankcases
Carbon deposits...from the products of combustion (blow by)
Sulphuric acid formed through the combination of carbon deposits and the water (although very small amounts)
Varnish like deposits from oxidised oils
Plus a load of toher constituents !! | 
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