So a common question I get for some reason sterling silver is leaving black traces on the skin. Why is that and what's causing it? Here are 2 reasons this might be happening.
The most common reason is there might be some polishing compound traces on the ring that were not 100% cleaned off! It happens, and it's something I try to avoid, but sometimes it's hard to see as the ring looks clean! The quick fix for this is a quick wash with soap and hot water and it should be good.
Another cause is it can be starting to develop silver oxide on the surface, which can also stain your hands as well, and can cause blackening on the silver. That can be caused by a few different things. Because sterling has 7.5% copper, it can react to different factors. It can be caused by either environment, harsh cleaning chemicals, ocean water, or a person's ph levels in their sweat (someone who sweats alot and it smell somewhat acidic?)
For example, my best friend turns silver black very quickly. My chain, which I never take off and is always shiny, she can turn black in 2-3 hours in the summer. I also had a client who ordered a set from me. Her ing is in perfect condition, but their partner blackened their ring in a week(photo attached) within 2 weeks. I'm presently making a stainless steel set for them so they match again.
I've also noticed when I was in St. Martin on a family vacation my silver blackened while swimming in the ocean. I was able to clean it when I got back, so was ok.
For cleaning a ring that is blackening, here are my tips. At most pharmacies you should be able to find silver jewellery dip cleaner. Place it in the cleaner for 30 seconds and rinse off with warm water. It will remove the tarnish. Then take a polishing cloth to it polish the surfae again. Then I recommend he takes it off at night and gives it a quick cleaning daily. The other trick my best friend, the one who blackens my silver, found is when she showered, she washes her hair with Head & Shoulders and helps to maintain the silver and reduce the tarnish on rings.
Another trick is mix 1/2 cup white vinegar and 2 tablespoons baking soda together, then let your silver jewellery soak in the mixture for two to three hours before rinsing and polishing with a jewellery polishing cloth.
For cleaning a ring that is blackening, you can read more on it here; https://www.miansai.com/pages/caring-for-silver