The cleaning of fountain pens is one of the most misunderstood aspects of fountain pen ownership. If done regularly, the cleaning of a fountain pen is simple, quick, and easy. We recommend cleaning your pen after every other fill of ink if you use the pen regularly. You should also clean the pen if changing ink colors. If you have a collection of pens and plan to switch pens after each fill of ink has run out we highly recommend cleaning before putting the pen away. Nothing is worse for a pen than to have them sit with dried up ink inside for long periods of time!
All you will need is your pen, a paper towel or tissue, and some water. Pay no attention to those online who have recipies for "pen flushes" or sell "pen flushes". If you are the original owner of your pen all you need is water. Vintage or second hand pens you purchase online or from an auction or antique store may require such flush mixes and more if they are very dirty or clogged with decades-old ink.
One way to clean your pen is to dip the nib end into a cup of cool water. Next, twist the converter to draw water into the converter like you would when filling it with ink, then twist counter clockwise to flush the water back out.
Repeat this until you are satisfied there is no longer much ink color being expelled from the pen. Press the paper towel or tissue to the nib to draw any remaining water from the feed and grip secton of the pen. If there is little to no ink coming back onto the towel, sit the pen aside to dry.
A second method is to remove the ink cartridge or converter from the grip section and hold the nib, facing down, under some gently running, cool tap water.
At first a great deal of inky pigment will be seen running through the feed and nib. Once this clears, remove the nib section from the stream of water, hold a paper towel around the nib, place your lips to the back of the grip section and blow through it to expell the water from the nib and feed. You'll notice the towel is very inky. Repeat this process until there is little to no ink tint emerging onto the paper towel.
If done regularly, either of these methods you choose will occupy a mere minute or two of your time once you are familiar with the process, especially when using modern fountain pen inks like those from Diamine.