I am having a problem with some silver items developing a white film
on the surface after soldering. I have not encountered this problem
until recently. It doesn't appear to be a fire coat with the typical
red appearance and can only be removed by polishing with a chrome
oxide based polish. I am using a distilled water and sulphuric acid
bath to remove my boric acid and alcohol suspension residue.
Should I be using something else to pickle these items? I have been
manufacturing gold, platinum and silver jewelry for the past 25 years
and this problem has me puzzled.
Any help would be appreciated!