Not another oil thread!

[tommyardin]

You should never store an engine with dirty oil, the fine dirt/carbon particles can settle over long periods and form a hard sediment in the bottom of the engine sump, it will eventually break up but invariably it will be some time after you have changed the oil, so now you have all the sediment back in your new oil, your new oil is hardly measurably better than the stuff you took out.