How to clean technical pens

These are my technical pens

Prepare supplies: technical pen ink, tweezer and hot water

Lay your techincal pens down on a tissue paper

Here are staedtler and rotring technical pens. I lost my faber castel technical pens.

Separate the parts in the order as shown here

{Optional: proceed with caution. If not careful, you may brake the needle which is the most important part of the technical pen. Disassembling this precious parts are for hard to clean technical pens}