Blighted Type and Quantified Results

As a professor, I have access to many chemists and experts who are helping me learn about my type lice/type mold/blighted type that I read about constantly.

A few sorts were tested positive for lead carbonate, no lead oxide and small traces of Iron. They are coming next to test the air quality of my studio and best practices for protecting my current clean type from the lead carbonate happening again.

I also learned that the lead carbonate is actually a protective coat that the lead is creating to protect from further degradation.

We are meeting with the chemistry department next to learn what are the best results for cleaning and saving these 37 cases of type from this evil lead carbonate without poisoning me or my daughter.

I will continue the discussion as I discover the results. Many may already know these things, but I am still learning.

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An excellent initiative and a sound approach … science is all about verification.

If at all possible, you could encourage your advisers to publish (ideally here and hopefully simple) tests for the carbonate and recipes for prevention.

Best of luck with the project.

This is very useful work, many people look at the white deposits on old type and assume it is Lead Oxide. A scientific look at this will go far to relieve people’s concerns about what they are handling, although Lead Carbonate has it’s own set of concerns. Please report your findings. By the way, the best way to clean type might be the old way. I have posted previously about this, in short, I use a weak solution of lye and then an ultrasonic cleaner, followed by a dip into a weak solution of paint thinner and 30 weight oil to give the type a protective coating. So far, no Lead Carbonate has returned to the type due to the oil coating.



Today I met with Dr. Johnson, a chemist at the University of Dayton to discuss further how best to clean my severely damaged type.

Wrong Approach: I first used a white vinegar and lemon juice solution. This was proven to actually harm the type and only pull out more lead.

Appropriate Next Test: A diluted test of Muriatic Acid proved to be substantially safer and quicker. Our first round, we simply soaked for about 30 seconds and the amount of lead carbonate removed was almost 100%.

Lead oxide still remained. Next, I was instructed to do a wet sanding process, very gently to the sides and to test different soft brushes to clean the faces.

After this, coat with CRC-3-36 precision lubricant or a motor oil. Then wax with Johnson Paste Wax. This will protect any further lead carbonate from forming, as well as, seal in the lead oxide.

My new cases are coated in Johnson Paste Wax, but I will also coat with a Eurathane to seal and protect before adding the new sorts into the cases.

This should be a long process but not harmful. Once the type is wet, the lead dust is no longer a hazard. The wet solution will then be disposed of through Environmental Safety.

It also helped that Dr. Johnson was fascinated with how beautiful each character was that he cleaned. Such a beautiful day and one step closer to preserving history and these beautiful fonts.

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Sounds like a good plan, with the backing of your chemist. Just a quick thought, the paste wax I have on the shelf says it contains mineral spirits. Possibly, you could do the oil coating process and the waxing step together by diluting the wax in mineral spirits and adding oil to it. One dip and dry.

Re your case restoration: I can’t comprehend the use of a urethane finish over the top of wax. You may end up with a pitted finish peeling off as wax is not urethane’s intended substrate. Not easy to ever get right after that happens.


So are you saying that because I already waxed my new cases, I should not put the polyurethane coat over that? If so, thank you for that sound advice! I wish I would’ve not have waxed them.

No finish should ever be put “over” wax. If all your cases have been waxed already, I’d leave as is.

I also “cringed” when polyurethane-over-wax was mentioned.


I think the wax should be good enough. Urethane would also just build up on the wood if the wax were not in the equation and can be a sticky substance after a long age, it can break down or bubble or all kinds of problems…. Wax’ll let go of things easily and is more stable, and easier to touch up in portions that need it without requiring a sanding or stripping….

Wax is the way to have gone, don’t be sorry :-)

Oh, but- waxing the type? I’m not sure I’m very keen on that idea. Seems like in use it would flake off. Metal rubbing on metal. Then you’ve got wax contamination.
My thinking is that whoever advised you to wax the type was not necessarily used to putting the type into USE, and was thinking preservation but not actionable materials.

Clean your type thoroughly and put it into storage into climate controlled studio, you will not have this problem again provided it doesn’t get wet.

For years most of us thought the white type mold was lead oxide. Now we are told it could be lead carbonate. My question is where from does the carbonate come to combine with the lead? I would like to see the chemical formula.

PbCO3 is Lead Carbonate. The “carbonate” probably comes from carbon dioxide.

I would imagine Lead Oxide (PbO) and Carbon Dioxide (CO2) combined under the right conditions would be all it would take.

But I am not a Chemist

UPDATE: The previous phase of tests did not remove the full lead carbonate (lead carbonate happens when the lead leaks out of the type and mixes with oxygen which then hardens and acts as a protective surface to keep the lead from continuing to leak out)… much like how a pearl is formed.

The lead carbonate came back after the above methods, so….

Next, I bought an agitator and some non-toxic cleaners and I will begin with that process and be back with specifics.

I REFUSE TO LET THESE 37 cases of type go!!

Indeed dont let the cases go. But surely typemetal is a three metal alloy thoroughly mixed in the casting machine and more so during the casting process. satisfactory type can only be cast when the metal is well above 600 degrees C (perhaps I should add here that this is with ref to a Monotype Composition caster machine[ and I always understood that the tri-metal alloy ( 10 Antimony, 16 tin, rest lead) when well mixed and cast at the right temperature for that size showed none of the characteristics of its parents. I think you should talk to Fry’s Metal Foudries here in the UK at Mitcham in London who really know about this stuff.