Passivation or electropolishing are the ultimate answer, but on a lot
of projects, the budget just aint there to do it.
Most important tools to be carefull with are, as mentioned, sanding
discs and belts, grinding wheels, and wire brushes.
We write "SS" in sharpie on the back of the appropriate grinding and
sanding discs, wooden handled wire brushes, and so on.
Never had a problem with hammers, or drill bits, or punches.
One thing that does pop up a lot, though, is scrapes from forklift
forks- these show up as rusty scratches in a few days. We try to use
straps instead of chains or forks, for lifting.
Sometimes you get rusty scratches where you drag a piece across a steel
table top or sawhorse, too.
One easy solution, though not cheap, is to buy a portable
electropolisher. With this, you can derust scratches or spots on site,
later, when they show up.
You can get em from Walter and Screen Pro. These are DC power supplies,
like battery chargers but higher voltage, that you use with a mild
You could try a battery charger and some citric acid, it will do it,
only slower than the commercial models.