[MamaA]

Thanks Beanie!
I'd be inclined to not use vinegar in the final rinse cycle at all, I've used it twice on fleece/pul in 10 months at the start of the wash cycle (about 1/4-1/3rd cup in an x/l wash load as soon as the water's filled) we've used these nappies everyday with no side effects, still going strong 10 months later with no signs of wear.