Repairing Checked Lacquer with Dust/Mold Discoloration

I've been asked to recondition a very good sounding 60's vintage Saturn, hollow body guitar. It has no cracks, however the nitrocellulose lacquer is riddled with them (see pictures below). In the "Items for Luthiers" under the title Amalgamating Checked and Damaged Lacquer Frank, over 12 years ago, demonstrated repair of checked nitrocellulose lacquer using Ethylene Glycol Butyl Ether with the Dow trade name CELLOSOLVE®, which I have used many times successfully on clean finishes.

However the Saturn also has dust, and most likely even mold discoloration in those cracks. 

Is there a non-corrosive way to clear up the check lines before amalgamating them?

Stripping it is not an option. Any other "solution" will be highly appreciated.




Tags: Checked Lacquer, Dust/Mold Discoloration, Vintage Finish Repair

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I met a guy one time that was building Violins  one day I was in his shop and he was removing a dark mineral stain out of a pice of Maple he took out this little jar and a qutip diped the tip into the jar tuched the stain and it turned snow white. I ask him what was in the jar and he said it was 50 pecent proxide and you had to watch it  didn't burn you,  I have been trying to find it ever since. Mybe some one out there knows some thing about this stuff. Bill.............

Yes Bill:

It was also used by Norma Jeane Mortenson to make her hair blond:)

Its molecule is like water but it has an extra oxygen atom, which makes it an aggressive oxidizing agent, "chewing" up everything organic or inorganic it gets in touch with. That's why hydrogen peroxide is available in the pharmacy only as 3% solution, the rest is distilled water (although it's also commercially available as 35% solution for disinfection).

You can see its many uses here and hundreds of other places. Just google them...

I also have a violin which I'll never finish (like Bussotti in "The Red Violin":-) that was completely treated with H2O2, and I didn't like what it did to wood: it penetrates it too deep and makes it too porous. It maybe OK for wicker baskets and woodcarvings, or for spot removals on furniture and instruments, but not for extensive body clean-up, like the one I'm faced with.

That's why I sense that citrus based orange cleaner in the right concentration, and without additives like pumice, lanolin, wax, etc., might be the way to go. Does anybody have any experience, or is there something else out there?


I used to have a friend that builds rockets as a hobby. Not model rockets...rockets. He once talked to me for almost a hour about the development of a formula for solid propellant engines that he and his "crew" were working on. It included rubber from old tires as a "control". In short, he knows a lot about how to get a 12 foot long rocket to fly.  He said that most of the people he knows work only with solid fuels but that there was one crew that was working with liquid fuels, hydrogen peroxide figuring heavily in their plans as an "explosive" source of oxygen. He's of the opinion that these guys are "crazy" for working with it. (This from a guy that mixes his "fuel" in a mortar mixer in his garage. BTW a special license is required to work with this stuff.) I ask him how well the liquid fueled rockets flew compared to his rockets. His response was. "They don't, so far all of their rockets have blown up on the launch pad". Fortunately, they go to the high desert outside of Los Angeles to do this.


In low concentrations it's not dangerous but in the "will burn your skin" concentrations, it's not something to have laying around. You really are getting in to the "rocket fuel" territory at that point.  In (much ) lower concentrations, it's a fairly effective protein cleaner. Most of the hydrogen peroxide available to the public is diluted with water to the 5 or 6% concentration level.  It's good at cleaning blood and other protein stains and really could be good at cleaning the kind of gunk that might buildup in the finish cracks on a guitar. I've never tried it.There would be a lot of moisture involved and I'd want to test pretty carefully to make sure that the foaming action that attends it's cleaning didn't get under the finish and create more damage. It might be worth investigating.



Thanks for the info, Ned.

It's too aggressive, I know: I also used it on shells and sand dollars my kids picked up on the beach, so I know how much it foams.

And it's more viscous than water. So, I wouldn't wan to try it on this moldy-oldie. Once the H2O2 is in the cracks, the capillary action won't allow the water to dilute it so easily. Even if I completely dunk it in distilled water:-)

Anything better than that?

OK, this my major question:

Does anyone know of a product containing Lemonene (typically used to remove engine oil)

or a different chemical specifically formulated to use as a cleaner on checked nitrocellulose coated wood?

If so, what are the end-results, and are there any undesirable properties and effects?

(e.g. Lemonene is not water soluble, needs to be mixed with a surfactant to be soluble, is also used as a paint stripper, dissolves polystyrene, stamp glue etc.,..what else?)


Here are a couple of web links I looked up on Lemonene :


Zack, it seems like this has got way off track,  most of the acid/petrochemical based cleaners will carry dissolved/lossened  dirt out of the crack and onto/into the substrate (wood) where it will remain trapped under the cracked finish and the  possibly compromised bond area between the lacquer and the wood.   It is this process that will make the guitar ugly and this will then remain the case if the guitar is refinished.   There is no magic bullet here - you have all the necessary  advice you need and are going to get as far as I can see.  

Re Naptha and Gibson:   as was previously said - the sticky and plasticised nature of some Gibson finishes is a combination of their own work and environmentals,  - Naptha remains the industry standard for difficult and not so difficult cleaning and if used correctly has no downside. 

I would tend to agree, Russell: 

Naphtha is one of those petrochemical cleaners - it did it to that check line under the fingerplate.

In fact in many languages "naphtha", "nafta", etc, is the word for crude oil.

And it's also not water soluble.

Here's my thought: Many of us, who sometimes get our hands dirty under the hood of our car, are familiar with the cleaning effect of the orange/pumice shop cream. It seems to be more gentle on our skin than petrochemical cleaners, and it even cleans off the black dirt under the fingernails (so your better half doesn't get repulsed when she looks at them:-)

This is why I am so curious about the findings re. lemonene. It competes with naptha as a solvent AND appears to be more effective as cleaner for heavy, petrochemical grime. - After all, they now use it as engine parts cleaner instead of naphtha...

I have another week or so before I have to make a move, so if anybody discovers something else, please fill me in.

If however I've gotten, as you say, "all the necessary advice" I can get, I'll do some exploring on my own, and report back.

Thanks everyone.

Sorry to dig this one up....but it came up when 'googling'!

I guess Ol' Zack...evaporated into the Ether-Land....????

That was some intense dialog....Ha!

The funny thing is that the guitar looked great for the vintage and would look stellar with any one of our 'routine' cleanup schedules....but he was 'stuck on' Agent Lemon....I am only curious on how that worked out for him???


The reason I'm not as active in this forum is that my primary focus is restoration of antique violins.

Re. cleaning schedule, I switched completely to Lemonene cleaners: As it turns out, it is an excellent substitute for naptha; just as effective, but it's water soluble, emits less obnoxious fumes, and is more environmentally friendly. 

There is a "happy ending" to the Saturn story:

I liked it so much AS-IS, that I traded a solid body Mansfield (a Japanese Les Paul lookalike oldie) for it.

However, like naphtha, the Lemonene didn't completely wash out the dark lines in the wood along the lacquer check lines, but I'm OK with it. After three cleaning and drying cycles (lasting a couple of weeks each), I applied the amalgamator, to add solidity to the body. Like you, Kerry, and some other contributors to this discussion, I have no problem with instruments showing their true age, as long as they are perfectly set up and functioning.

Thank you very much for all your contributions to this discussion!

Zack out

Hey Zack,

 I'm curious about these Limonene cleaners that your using. After looking into it, I found it in a few different products (like ZEP degreaser mixed with a few different ethers), as well as available in pure form. What have you been using specifically? 


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