I purchased a set of Rapidograph technical pens on ebay. The seller said this was an unused set of pens. YIKES! this was definitely a case of buyer beware. The pens were not only used, but frozen from dried ink. The ink contains a shellac and they are next to impossible to clean when that happens. The box smelled like old stale cigar smoke. The entire thing was NOT a pretty picture. I could ask for my money back and instead I asked for half of my money back.
I will always go to great lengths to save a buck or two if the end result gets me what I want. The first photo shows how dirty the pen points were. The book it is laying on is “The Technical Pen” by Gary Simmons. I didn’t know when I bought this book at our Salvation Army [new condition] that it is the bible for technical pens. I paid $3 for the book and I saw it on amazon for $55-$150. My mom always said I could fall into a pile horse manure and come out smelling like a rose.
The second photo shows what the inside cartridges looked like. This is actually a cleaner one. The last photo shows the dried carbon pieces I was able to break out of the cartridges before I could even think about cleaning them.
It has been 2 days since I started the process. I soaked the pens in a 20% ammonia solution and all the refillable cartridges came clean along with the pen bodies. So far so good. I could hear the weight and wire moving around in only one pen. I figured they weren’t going to be useable unless I got them clean so my next step was to take a more radical approach.
I soaked them in straight ammonia overnight. This morning 4 pens are finally rattling. 3 pens are still frozen. They will go into a straight ammonia solution for another 24 hours and I’m hoping for the best.
I have a set of these pens that uses the capillary cartridge. I want to be able to fill these with acrylic inks to use on my fiber art. My dear husband Ron has asked if he may take over the cartridge set to do a little drawing and sketching. I want to encourage him to do that so I HAVE to get this other set clean and useable. He has done pyrography in the past and liked it. I think the pen drawing will be a more immediate source of gratification for him. Wish me luck!
Janice Paine Dawes, Artist 
Good Luck Janice! We used those things in architecture school ALL the time! That was in the '70's and early '80's before computer drafting. What a nightmare they were to keep clean and functioning! Great that you got a book – we had to learn from expensive experience. If you take the tiny wire-like point out of the cartridge you will probably never get it back in. But I bet the book warned you about that, eh?
Lol, the book warns against that. But it has a diagram of how to let the wire reseat itself if it should come out by mistake. One online source said she keeps all of her points in a small bottle of ammonia and never leaves them in the pen case so I might give this a try once I get them working.