How to refurbish plotter pens?

[Jon Elson]

On 01/19/2019 03:57 AM, Mattis Lind via cctalk wrote:
>
>
> All my pens were obviously dry. Refurbish a pen seems to be impossible.
Well, leaving them in alcohol for a few days seems to slowly 
seep in and soften the dried ink.
Most have hair-thin wires that run down through the pen 
"needle" and these will break if too much force is applied.  
Once the ink softens enough to allow the weight to be pulled 
out safely, then the pen can be cleaned more easily.  An 
ultrasonic cleaner helps a lot with this.

But, I have to admit, my success rate is no better than 50% 
(but I don't have an ultrasonic cleaner.)

Jon