How to Clean Waterproof Ink from a Fountain Pen

If you are in the pen world for long enough you will come across waterproof or permanent inks. And, if you buy one of those inks, at some point you will leave it in a pen for too long, leaving your nib and feed clogged.  

The best place to start when it comes to cleaning waterproof ink from your pen is to start with the pen itself. How do you choose the safest pens for waterproof or permanent ink?  

I would ONLY recommend putting waterproof ink in a pen that can be totally disassembled to clean and where you can also buy replacement parts if something is unsalvageable from the ink. While 99% of waterproof fountain pen inks are completely safe, some can cause damage with long term usage/storage in pens. When it comes to waterproof ink I find the most foolproof system is to designate one pen in your collection your ‘waterproof ink pen’ and never let it dry out completely, But, sometimes the best plans go awry and you do need to clean your waterproof ink pen.

⚠️IMPORTANT⚠️

These instructions only apply for a pen that has water submersible parts. DO NOT do this with a celluloid pen or anything similar product that dissolves with extended exposure to water.

Sailor 1911 Fountain Pen in Call of Cthulhu resting on a notebook with a piece of paper towel and two cups

Step 1: The Prepping the Area for Pen Cleaning

Unlike other pen cleaning projects, before I start to take apart a pen inked with waterproof ink I want to make sure I have a roll of paper towels on hand and the work surface is completely covered so that it doesn't get stained. I also find it useful to have 2 parts bins; one for parts that need to be cleaned and one for parts that don't.

Step 2: Disassemble Your Pen

You will get ink on you. If there is any speck of wet or wet-ish ink still in the pen it will find its way onto your person. The last thing you want to do is crack or strip any of the pieces.

If the nib, feed & housing separate; that will all come apart because I find they don't stand a chance of coming fully clean without being disassembled. If there is still ink in the converter I will carefully empty it into the garbage but if I am using a cartridge I just throw it away.

The pen body and cap go into my "clean" parts cup as I won’t leave them soaking in water. They will be cleaned with a q-tip.

Sailor 1911 L Call of Cthulhu Fountain Pen disassembled on a rhodia notepad
Sailor fountain pen parts soaking in a cup of water

Step 3: Warm Water Soak

Bathtime for the nib, feed, housing, & converter. You don’t want this water to be hot but I find that lukewarm/warm water definitely seems to help in the ink softening process. Make sure you flush water in and out of the converter a few times and then leave it sitting full of water.

Change the water every few hours for 24 hours.

I normally just let the grip soak for 10-20 minutes and then rinse it off as I find that most of the ink that ends up on the grip tends to end up on my hands when using the pen so the grip tends to be fairly clean.

Step 4: Pen Flush

I didn’t realize how useful pen flush was until late 2024 when I could not get ink out of a few second-hand pens I bought. While there are recipes on the internet for DIY versions, I recommend sticking to branded versions due to their testing and batch consistency.

I find it best to fill the converter with pen flush and then to leave the nib, feed and housing sitting in a small dish of it for 6 hours to overnight.

After letting the pieces soak, rinse everything thoroughly under warm water.

Step 5: Assess & Repeat

Unless you have a particularly well-behaved waterproof ink you will have to repeat steps 3 & 4 a few times. As the process goes on though, the number of pieces being cleaned will reduce. I find that the converter and feed tend to take the longest to clean and the metal nib tends to only need one cycle of wash and pen flush.

I repeat the cycle until I get the feed clean. A tiny bit of residue in the converter isn't a huge deal normally but if you have waterproof ink stuck in the feed, it can cause some major flow issues.

Rinsing a Lamy Safari front end section under running tap water

Step 6: Rinse Parts

After the pieces have their last soak in pen flush, I let them soak in warm water for 5-10 minutes before rinsing off each piece individually under running water. Make sure to use a plug in your sink so you don't lose any pen parts down the drain. If you skip this step, please refer to youtube videos on how to retrieve items from a P-trap!

Step 7: Dry

Drying a pen and the parts is so simple and so incredibly important. If a pen isn’t fully dry, parts may rust or discolor over time.

I use a tray lined with paper towel as my drying setup and pen parts stay there for 24 hours or until I remember I cleaned pens, whichever is longer. My drying setup is over the top for most people but because I batch clean pens, it is really important that my pens have a ‘landing spot’ where they can safely dry.

 

Sailor 1911 fountain pen parts drying on a paper towel

Step 8: Re-Assemble

This is the most important step in the entire process, take your time. I find disassembling a really fast task but when it comes to re-assembly, this is your time to look all the parts over and make sure everything is clean & nothing needs to be replaced.

Step 9: Re-Ink or Put Away

Now that your pen is clean it is time to make an important decision, re-ink with waterproof ink or water soluble? Or are you storing your pen for another day? Either way, hopefully this article helped to answer some of your questions about cleaning waterproof inks and has helped you to feel more confident in using them in your fountain pens.

How to Disassemble a Sailor Fountain Pen for Cleaning

In this article, we showed a Sailor 1911 fountain pen being disassembled and cleaned. To watch step-by-step instructions on disassembling a Sailor fountain pen, watch the video above and follow along with your Sailor 1911 or Pro Gear fountain pen.

About the Author

Alexandra Richardson is a Canadian watercolour and fountain pen content creator. She can be found on Instagram and Youtube under @alexandrasartinsanity.

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