I'd like to preface this with saying I've been a bike commuter for just about one year now and still know very little about bicycle maintenance, just the basics. Anyways, I live in Buffalo, NY and kept my bike away for the winter and it stayed in very good condition.

Last weekend I rode it to my grandpa's birthday party through the rain. I was so exhausted that I left it in their shed and just got back to pick it up (the weather's finally perfect biking weather). Anyways, I started riding home and looked down and noticed my chain has developed quite a bit of rust in its 9 day stay in their shed (which I guess didn't surprise me that much because everything in their shed is rusty...).

So what's the best way to remedy this? Surely I don't need to get a new one yet, right? I'm really not certain about what to do because like I said, I'm pretty unknowledgeable when it comes to bike maintenance and I'd rather admit defeat and get help than really mess it up.