Yeah, just regular 10% vinegar. It's not fast, but it's pretty gentle, which is a good thing. You don't want to remove as much as possible, you want to remove as little as necessary.
The main reason to use citric acid is to passivate stainless steel. For any metallurgists out there, I know passivation is the wrong technical term, but it's the common usage to describe stripping away the oxidation that forms on stainless over time and has converted to red rust. Once stainless converts to red rust, it will continue to rust (although a little slower than mild steel). You need to strip away the top layer of oxidation, and "re-set" it, so to speak. After treating with citric acid, you can polish easily. If you don't need to deal with stainless a lot, I'd say that it's not worth dealing with. Plain ol' vinegar will be a better first step.
Thanks Joaquin, that's a great description! I will start with 10% vinegar and a few tests with 70% Vinegar and the citric acid on a few little parts to see how it will work!