Point of order: BP fouling is not corrosive as such, it is hydroscopic, so it does suck in water, but the nastiest chemical agent needed to shift it is water.
While the non-believers scorn BP fouling for being so hideously dirty, I just push one or two tight, wet patches through, one or two tight, dry ones, then one oily one. Then I go and enjoy myself while the smokeless crowd fuss with various chemical solvents.
RG