Never use a wire brush on stainless.
Good advice, excepting that it should be a non-ferrous or stainless steel brush. Bronze, nylon, stainless steel are OK. You also have to be careful when working with stainless and you contaminate the metal with plain iron.
On another note, all stainless steel can rust if its exposed to the wrong environment. In the brewery, the most hazardous environment typically arises from high chlorides. Using bleach or hydrochloric acid on those metals can be detrimental. The grade of the stainless steel also has a large effect on its corrosion resistance. The cheap stainless that is often magnetic, is more prone to corrosion. The 300 series steel is typically more corrosion resistant. I have to deal with this issue in wastewater treatment. 304 stainless is sort of the bottom line and I have to move up to 316 steel when the corrosion conditions are more severe. I did some work for the South Florida Water Management District years ago and had to spec an even higher stainless grade (317) because it was exposed to seawater. From my experience, brewery use most typically needs only 304 stainless. Just be aware that you can screw that up if you expose it to too much chloride during some sort of cleaning operation.
I was told the same thing by my keg supplier "all SS can rust". I've had an ongoing issue with small rust showing up on the welds of the keg lid handle. Maybe this technically isn't SS that's rusting but the weld.