Rust on a watch appears where moisture lingers longest: between the links of a steel bracelet, around the clasp, on a strap buckle, on the caseback and under the bezel. Sweat, pool water, salt and damp winter air affect even steel, and cheaper alloys rust faster still.
Left alone, rust keeps spreading, weakens the links and can reach the seals. The good news is that surface spots are easy to remove at home in half an hour, as long as you work gently and keep liquids out of the case.
What you will need
Important: Do not spray products directly onto the watch and do not submerge it unless you are sure of its water resistance. Keep the crown pushed in. Sandpaper and steel brushes scratch polished steel, so keep them away from the case.
Step 1
Remove dust and grit
Wipe the case and bracelet with a dry microfibre cloth to remove dust and sand that would otherwise scratch the surface. Detach the bracelet if you can.
Leather or fabric straps are best removed entirely, as they need neither water nor lubricant.
Step 2
Wash the bracelet with soapy water
Dip a soft cloth or toothbrush in warm soapy water and go over the links, clasp and caseback. Only wipe the case with a damp cloth, do not soak it.
Step 3
Dry thoroughly
Pat the watch dry with a towel and blow out the gaps between the links with a hair dryer on a cool setting. Water left in the hinges causes new rust.
Step 4
Treat rusty spots with WD-40
Apply a little WD-40 Multi-Use to a cotton bud or the corner of a cloth, not to the watch itself, and dab only the orange spots. It creeps under the rust, displaces moisture and loosens the bond between the deposit and the metal.
Leave it for 3-5 minutes. Excess only collects dust.
Step 5
Brush away the loosened rust
Gently clean the treated areas with a soft toothbrush, and use a brass watch brush with light pressure in the bracelet gaps. Spots usually come off after a few passes.
Deep pitting on the case or bracelet is a job for a watchmaker, as polishing needs special compounds and wheels.
Step 6
Wipe off residue and protect the metal
Wipe the watch completely dry with a clean microfibre cloth. The clasp and hinges can be cleaned further with WD-40 Specialist Contact Cleaner on a cotton bud: it evaporates quickly and leaves no greasy film on the skin.
On the inner side of a steel clasp that does not touch the skin directly, you can leave a barely visible film of WD-40 so that moisture does not settle.
Tip: After the pool, the sea or a walk in the rain, rinse a steel bracelet in fresh water and dry it. In winter, never put a wet watch in your pocket: that habit causes more rust than any weather.
What next
A monthly check of the bracelet and clasp keeps your watch going for years. The compact WD-40 100 ml fits neatly in a drawer next to small repair tools, and if rust appears on the movement or under the crystal, take the watch to a workshop.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
More guides in «How to use».