. . "The method of claim 23 wherein the boron compound is selected from the group consisting of a metaborate, a boric acid, a boric oxide or an alkyl borate of the formula:wherein x is 2 to 3, y is 0 to 2, the sum of x and y being 3 and R.sup.2 is an alkyl group containing from 1 to about 6 carbon atoms." . .