Oxalis is my choice. Not so toxic. Easy and relatively safe to store and handle. A concentrated solution removes rust stains in about 30 seconds.
I'd avoid muriatic (pool) acid as contact with stainless steel
can form ugly and difficult to remove chloride blush. Similar problem with many other acids such as nitric.
Chlorine bleach is a great rust producer (oxidizer), so not do sure it's a good idea. But I'm no chemist.