Bicycle Mechanics - Rust

because of snow it caused my chain & sprockets to get pretty rusted. what would be the best method of cleaning off all the rust?

Well you could remove the cogs and scrape them with steel wool. I did that and got a decent amount off, using WD40 eats at rust. Then using a good oil lubricant like triflow helps prevent it from coming back.

If it is minor rust(like if you catch it right away) you can often get it off with a 3M scotchbrite pad. Not the kitchen ones, the sheet ones you get at home depot or the like. They fit in the cogs nicely and usually have enough abrasive to scrub the rust. Surface rust is not a really big matter unless it is really pitting.
The preventive measure that works best is to never put up wet. Always dry the bike and lube the chain before packing in after rain/mud/snow rides. Feels like more work the day of, but it makes the next ride so much easier. On my bikes I have the pins removed from my cassette cogs, allowing individual access for polishing. Whenever I do a rear hub overhaul, sometimes sooner, I take the cassette apart and use a good carnauba wax on them. It lasts a good long while and won't cause any side effects. Not to mention it makes them nice and shiny :)

Spray some wd40 on the sprockets and chain. Let it dry off a bit, then add some chain lube to the chain. The rust will not get any worse and will wear off at contact points.
Don't let wd40 spray get into the seals of bearings at wheels or BB.

Thanks for suggestions. What do you think of soaking the peices in a bath of clr?

I would be leary of doing that. CLR is hydroclhoric acid, which can damage metal if overexposed. If you use it, be very very sure you rinse it effectively to deactivate the acid. In my experience abrasives such as steel wool or scotchbrite are far better suited to the job. As was stated it is not neccesarily critical to remove all of the rust, just make sure it is oiled/not active. In some applications(not mtb) I have found a light coating of rust holds oil in its pores well.

CLR is brutal, i would not do it. ITs simply not necessary, if your cogs are that badly rusted than replace them. If its just a little bit on the teeth forget about it. I got rid of what i could using steel wool and the rest came off in time.

Was it just looking badly rusted, or was it noticeably stiff to pedal backwards. I've had bad looking chains before that turned out to be just brownish dirt mixed with minimal rust that came right off. My commuter bike gets no attention all winter. It's my experiment in how far you can push the "no maintenance" thing (plus it's definitely not an attractive target at the train station). It recently sat for a week while I was out of town and now looks very rusted (chain, sprocket) and feels stiff. But once I start pedaling it loosens up pretty well. I'm forming the opinion that you can go a long way on pretty rusted out looking chains.

Its quite rusted, when i move pedal back the chain begins to come off the sprocket. Pedalling backwards is impossible. Haven't tried normal riding yet.

well, you might be able to help that out with enough lubrication but if thats that badly rusted you might as well replace your cassette/chain. I recommend the SRAM PC69. It seems to be alright with not getting rusted.

And one more thing, use a heavy lube if your riding now. In winter i always use Pedros Synlube, its a crap magnet. But it lubes really well, protects against water and does not easily get washed away

Sounds good, thanks for all the advice.

You can rework a chain from a pretty rusted state as well. I have done some that had to be turned by pliers initially. WD-40 and work it back and forth. Clean it again afterward and use an oily lube like the afore mentioned pedros. Sometimes in winter on the beater I will use plain motor oil. It requires more cleaning, but at 1.20 a quart its a lot cheaper when it needs reapplication every other ride either way. On the race rig I use Pedros or Finish Line XC. For as cheap as they are, I replace my main bike's chains every spring.