I would stay away from using "polishes" or other chemicals on the grates that you cook your food on.

I'd suggest putting them on the grill and heating them up to the highest temperature possible for ~30 minutes or so to burn off any toxins. Then scrub with a grill brush. If they don't look satisfactory then buy new ones.

If they're really rusty, I question whether or not they were stainless to start with.

Are you talking the grates or the actual surface of the grill lid, frame, etc.?

If the grates, try burning them off. The cleanser, "Bar Keepers Friend" works wonderfully on stainless cookware combined with a blue ScotchBrite. I would imagine it would also works well on grill grates. Maybe use one of the green Scotchbrites since the appearance of the grates doesn't matter.

Thanks for the quick reply & sorry for MY real LATE reply -just now getting back my pc from being repaired. Actually I was talking about the surface of the grill I tried some BBQ grill cleaner by SPRAY NINE and it came out pretty good all the rust spots (on the surface) came out. still has some blemishes but all in all looking much better.
Thanks again guys & sorry for the delay getting back to you.
Bill