Sodium hypochlorite is simply household bleach. Sodium hydroxide is more powerful, also known as caustic soda, used in all manner of industrial processes. You can still buy it in anhydrous form (dried granules), very useful for melting away organic matter in drains. If you get it on your skin, in a few minutes your skin will get slippery - that's your skin being dissolved. After dipping rings in this brew I'd be sure to remove it completely, ideally a long bath in the ultrasonic. Both these chemicals will dissolve precious metals, but it takes days and weeks, unlike acids, which act much quicker in the proper blend. I worked in a chemical plant that made $1 million dollars of this stuff every 11 days - and that's a lot of RR tankers. All the process lines were made of nickel, the metal most resistant to its corrosive action. Being a base, it is neutralized by a proper amount of acid, one of the first things done at a water treatment plant. I wouldn't worry too much, its just another of the thousands of toxic substances which make modern life so pleasant.