I am using a silver solder paste that contains potassium difluorodihydroxyborate as flux. What is the best way to remove any residue of the flux after soldering? As the ring will most likely be worn 24/7 (i.e. also during food preparation and things like that), I want to avoid the possibility of any flux remaining on it. I usually pickle my rings after soldering in a vinegar and salt solution and afterwards I brush/polish them thoroughly with a metal brush under running water. Is that enough to make sure the ring is flux-residue-free?