Somehow I got metal shavings on the deck and the swim platform ...what can I use to remove the stains ?

Mike, you caused me to have to get up go out to my garage to look for the name of the stuff. I didn't find it, but I did remember the name while I was looking. It's called FSR (fiberglas stain remover). It's a blue gel you let sit, then wipe it off. It takes off most stains. I've had to sand some off before. I think it depends on how long you let the rust sit. You can get it at any marine supply store.

You could also try CLR just be careful how long you leave it and don't get it on skin.

thanks guys .. give em a try .....the worst now is on the swim platform ..on the non skid part ...

Alumabrite. This is a basic (not acidic) solution that will dissolve rust stains before your eyes.
Caution: Do not put on aluminum or stainless. This stuff was made to "etch" metals before priming. It will discolor your raw metals.
Available at all marine hardware stores.

Use Meguire's Wax ball and wax.

If all else fails sulfuric or hydrofloric acid will take it off. Sulfuric would probably be the easiest to get at a building supply store.

thanks guys ....