One easy way to keep your fountain pen working smoothly is to give it a simple cleaning about once a month.
1) Take off the cap and unscrew the barrel of the fountain pen.
2) Remove the ink cartridge. If it still has ink in it, remember to put the cartridge somewhere safe. Perhaps open side up inside a shot glass?
3) Hold the feed and nib section of the fountain pen with the nib pointing down under cool running tap water. Continue to do this several seconds until the water runs clear.
4) Use a paper towel to blot the water off the fountain pen nib and feed. It’s okay if ink is still inside the feed and comes out of the nib onto the paper towel.
5) Insert the ink cartridge into the pen, screw the fountain pen back together and put the cap back on. That’s it – you’re done!
(Woodpecker White Oak Notebook and Waterman fountain pen)
Simple and effective for most situations.
For a more thorough cleaning, you can try this fountain pen cleaning solution.by