Nevr-Dull, still using it after four decades and although
it's a bit dryer than it was new, it still works:
http://www.pbase.com/dennygraham/image/159317093/largeStainless steel will stain.....as Don posted, if rusty metal
or was in contact with it or if it was covered with something
that transferred to it, but those stains will come out.
Rust adjacent to a weld is often seen because there is a heat
effected band of the parent metal that cooled slowly causing
it to loose it's austenitic properties. It will also be
somewhat magnetic in this band.
dg