Shift the bike to the smallest chainring and smallest rear cog
Put the bike in a stand or place it securely upside down
Wipe the chain with a dry rag to remove dirt and loose grime
Apply a bike chain degreaser or penetrating oil to the rusty areas
Let it sit for a few minutes
Scrub the chain with a chain brush, stiff nylon brush, or old toothbrush
Rotate the pedals backward to clean the full chain
Wipe off loosened rust and residue with a clean rag
Repeat degreasing and scrubbing if needed
Use a rust remover suitable for bike chains if rust remains
Rinse or wipe the chain clean according to the product instructions
Dry the chain completely
Apply bike chain lubricant evenly along the chain
Wipe off excess lubricant
Check the chain for stiff links or severe corrosion
Replace the chain if rust is deep, flaking, or the chain is damaged
Clean and lubricate the chain regularly to prevent future rust