How do you get a broken electrode off a glow plug on a xsara Picasso 2.0 hdi?

To remove a broken electrode from a glow plug on a Citroën Xsara Picasso 2.0 HDi, first, ensure the engine is cool and disconnect the battery. Use a fine pick or a small magnet to carefully extract any loose fragments of the broken electrode. If the fragment is lodged inside, you may need to use a specialized extraction tool or a left-handed drill bit to carefully drill it out. If you're unable to remove it, consider consulting a professional mechanic to avoid further damage.