How many times have you bought something made of stainless steel, only to find it completely rusted after a short time?
As mentioned by Dog and others, good stainless steel is non magnetic. So when I found myself at the hardware store with my magnet in hand, I just HAD to go down the bar-b-que aisle and do some testing.
(I was there to buy some stainless steel bolts, and found nearly all the stainless bolts, nuts, washers, etc. etc. etc. at Ace hardware to be good, with the exception of some of the cotter pins. It was as if they got a refill of some inferior cotter pins. I plan to mention this to them next time I'm there.)
Here is a video showing my in-the-field testing of bar-b-que implements.
Click here for video (12.5 Megabytes)
I'm sure there must be good places to get non-magnetic stainless steel bar-b-que implements. The hardware store is not the place to go. Again, Ace had good stainless in nearly all their bolts, nuts, etc.