I’m not responding with a method for testing .925 silver, but will
suggest a simple method for removing tarnish. Be aware that once the
tarnish is removed, the surface should be polished to restore the
shine. NOTE: This method uses hot water, so delicate stones (opal,
pearls, etc.) may be at risk.
You need a glass container that will hold your jewelry, laid flat.
Place aluminum foil flat on the bottom of the container. Sprinkle
ordinary baking soda (start with 3-4 Tablespoons) on the foil and
place your jewelry in contact with the foil. Pour HOT water into the
container to cover the jewelry. You will notice the tarnish will
vanish and you’ll faintly smell sulfur. If the piece is heavily
tarnished, repeat with new foil and more baking soda. Use plastic
tongs or rubber gloves to position pieces.
I’m sure a search of the archives will reveal a more comprehensive
description, and I vaguely recall a report that washing soda is even
more effective than baking soda. (I’ve only used baking soda.)
Judy in Kansas, who is rooting plant slips and getting seedlings
started… time to plant in another month.