- If you drop it, then pens will break and be useless. These pens write with a thin filimant wire, if it breaks off/ gets bent the pen will know longer write.
- The smaller the tip of the pen, the easier it will break. DO NOT use the small ones on textured paper, for instance, watercolor paper. Lint from the paper will get into the tip and break it.
- make sure you have pen cleaner such as rapidoease. Dip the pen tip in between drawing sessions to prevent it from clogging. And completely clean with it when you are done using the pens for awhile.
- If the pens have dried ink, submerge them in the solution. Then rinse with water. For really clogged pens fill the ink reservoir with the cleaning solution and let it sit so it can clean out the pen from the inside.
- Koh i noor make a special bulb for cleaning but I have not purchased one, as they are expensive.
Here's a piece of mine done using these pens. Feel free to ask any questions about these pens ^_^
One can purchase these pens from the above link, ebay, or online art stores. Some physical art stores sell these pens, but look online first to make sure they are selling them for a fair price.