Cleaning Rapidographs - even the ancient crusted ink wasn't that bad

I just finished refurbishing my 20 yr. old Rapidograph set, which was
stored, full of ink, about 10 yrs. ago. Some mechanical cleaning
action, scrubbing with Qtips and a toothbrush, made this job not too
hard at all. Other methods/suggestions I've found don't mention
anything like this, and often say that the pen mechanism can just be
clogged beyond recovery. I bought some Rapid o eze cleaner, but other
things will probably work as well. 409 was suggested previously on
this forum. I also bought the little pressure bulb cleaner, which
again was helpful but, I found, not crucial.

Check out this page: http://www.koh-i-noor.com/index2.html

The recommended use and maintenance here is good. Note the frequent
use of Rapid o eze to keep things flowing and clean. For this reason,
buying some for the initial cleaning is not a bad idea.

OK, the real clean out: The cleaning instructions on the above linked
page are good, but won't really do the job for old, crusted ink,
especially on the smaller tips. The dry ink can glue things together,
so break the pen down as far as you can and soak in cleaner for a
while. Once you can unscrew everything,
link to "See Pen Components" From the above linked page. This is an
exploded view of a Rapidograph pen. But it's not fully exploded! It
shows the nib section as if it were just one part. It actually has
three parts. A little cap pops (or screws, on older pens) off, and a
small metal rod, the plunger, will slide out, or will require more
soaking before it will slide out :-) Careful with this as it has a
very small wire on the end of it which fits through the inking tip. I
suspect the fragility of this wire is why breaking down the nib is not
recommended by Koh I Noor.

Qtips are your friend. Just clean all the tiny parts with running
water and Qtips dipped in the pen cleaner. Get inside the 'pen body',
the ink cartridge, the little cap from the nib section, and especially
inside the nib tube, where the plunger goes. This seems to be the main
culprit as far as dry ink clogging. You'll find the Qtip fits tightly
in there and will act like a syringe and squirt water out the tip.
This is why the bulb cleaner isn't really necessary. Use the wire on
the end of the plunger to ream out the tip from the front end. This is
like threading a tiny needle so CAREFUL or you could bend and ruin the
wire. A toothbrush dipped in pen cleaner is great for the plunger and
the threads on the nib and pen body.

Rinse everything really well with water. Use more Qtips to dry inside
all these tiny little doohickies. A can of Dust Off or similar is
crucial to finish getting everything really dry so there's no water
mixing with your ink when you fill up the pens.

I was able to sort of discover all this and restore my encrusted set
of six Rapidographs to like new in a couple hours. Hopefully this post
will make it even faster for you :-)

Peace,
Sanaka