Good pen hygiene will keep your pens writing well and you happy for years and years to come. Depending on the inks you use regular cleaning will keep things working well. If you let your pens sit for a long period of time, especially with glitter or some other fancy inks, don’t be surprised when they stop working and a simple flush isn’t enough to clean them out.
If you have something hard to clean out I would recommend a mix of ammonia and water, about 1 part ammonia to 10 parts water. Then a final rinse with water. Sometimes an overnight soak is necessary. I like to fill the pen with the cleaning solution and leave it overnight.
Every now and then though, you get something nasty at the pointy end of your pen, or in a bottle of ink.
What to do?
With that contaminated bottle of ink, whether it’s fuzzy mold on the top, or a glob of jelly deep inside, it’s easiest to just toss it. It’s not worth getting your pens sick. Ink is relatively cheap, especially compared to your fine writing instruments.
When you have fuzz on the nib? Oh buddy. Things are serious now.
You can use a mild ammonia/water mix to clean parts with. With mold, a flush won’t be enough, so taking your pen apart for a good deep cleaning is best. If you don’t know how to take your pen apart, get help.
Here’s a moldy Pelikan. Two runs through the ultra sonic cleaner with ammonia water, and a good scrubbing with 409 inside the barrel and cap parts, and we should be good to go.