Clean and lube the chain; the shop will take care of the rest
Simple yet sophisticated, the bicycle chain is arguably the world's most efficient and reliable propulsion device -- when you take care of it, that is. Here's how:
||A Little Lube'll Do Ya|
The best way to keep links looking good is by getting a quality chain lubricant and applying it sparingly. Buy lube at a bicycle shop because shops stock and know what's best. To lube the chain, work in the garage or over a piece of cardboard and apply a drop to every other link. Do this anytime you notice that the chain is beginning to look dry. The sign that you've waited too long is a squeaking sound while pedaling. Riding on dry links wears the chain and sprockets prematurely (it's harder to pedal, too). So lube the chain immediately.
When you apply lube, let it sit a bit and then wipe off the excess. You don't want excess oil on your chain because it picks up dirt (which makes things wear faster) and increases the amount of grime that builds up on your sprockets and shifters. A messy chain marks you with hard-to-remove grease tattoos anytime you get near it, and it'll do the same to your car if you transport your bike in it.