If it is stabilized turquoise you could try the Calgon (or Arm & Hammer
Super Washing Soda) and water with aluminum foil. Be careful, don’t let
it sit in the solution. Just a minute or so and rinse. It may take
repeated steps or you could suspend all but the tq part in the solution.
If it isn’t stabilized I would use Flitz metal polish with a Selvyt cloth.
After you get it clean, wrap in jewelers tissue, and keep it in a zip
lock bag with a 3M anti tarnish strip.
I have used the Calgon solution on tq (both stabilized and unstabilized)
and haven’t noticed any color change, but long term it could have an
effect. Of course, don’t use Tarnex or you will still have to take apart
and polish each and every piece!!
This is what I would do, but glad you asked, I’ll be interested in other
ICQ # 9472643
Bacliff, Texas Gulf Coast USA