How I fixed a Citizen Eco-Drive wristwatch

After 10 years or so it started to slow down
So I removed the back

That MT416 is not a battery but a backup capacitor so out it came for a clean, I used a wooden cocktail stick to wiggle it out. Use a metal probe at your own risk and don't touch the mechanism with bare fingers. It's 4.6mm diameter so you'll need good eyes or a magnifier
Note the tab at about 10 o'clock

Clean that contact, I used a cocktail stick dipped in methylated spirit. Don't use a cotton bud or you'll risk leaving hairy debris

Then I cleaned the capacitor contact surfaces and bent the brass tab out a smidgen with the cocktail stick
Carefully reassemble with the tab properly orientated and replace the back
Hope for the best

The End