The single advantage of a nickel pickle (Potassium Dichromate, a.
k.a. potassium bichromate) is that once mixed into water it lasts
far longer than using a solution of granular hydrogen peroxide (like
Oxi-clean) and phDown or sodium bisulphate (one common brand is
Sparex*#2 *) which can be used with silver, and copper containing
alloys while straight nickel pickle(s) can not be used with silver at
all. unless you want to use it as a patina because it will definitely
change the colour of silver. In fact there was a solution
(Schwerter’s Solution) made years ago that was used to test silver’s
purity. You have to store nickel pickle in a glass or ceramic
container with a lined or enamelled cap or better yet a glass lid- It
is very carcinogenic in its pure state according to OSHA. So not
something to play around with. Store the unused material properly.
Never boil it- but, if warmed in a pyrex pan or beaker ( or warm in a
dedicated pot on the lowest setting of the pickle pot or " crock
pot") don’t stand over the open container, use a respirator with
filter cartridges and take all standard chemical handling
precautions -Some crock pot brands use glazes that don’t last very
long when the pickle (any pickle, even ordinary sparex, pHdown, etc.)
stored in it 24/7 .Do check your "crockery liners frequently for
signs of pitting, etc.
around the liquid line for problems. You may start seeing strange
results when you pickle silver, 14 karat or lower- well, even 18 kt.
now that I think about it…-once the liner begins to age. the
stoneware the liner is made of often contains iron oxides and it
leaches into the pickle solution at which point time to buy a new
liner ! If you are lucky enough to find a “crock pot” type cooker
with a glass liner when setting up your studio go for that type from
the beginning; you’ll never have to change it out! Hope this helps.