How can I effectively clean and maintain a bike with a rusty chain?

To effectively clean and maintain a bike with a rusty chain, start by removing the chain and soaking it in a degreaser solution. Scrub the chain with a brush to remove rust and dirt, then rinse and dry it thoroughly. Apply a lubricant specifically designed for bike chains to prevent rust and ensure smooth operation. Regularly clean and lubricate the chain to maintain its condition and extend its lifespan.