Tl;dr: Use naphtha, white spirit or diluted IPA to clean the clouding and leave it at that. Don't take advice from random strangers on the internet.
Abrasive polishing? I do not know as much as I'd like to about this stuff, all I know is that most of the internet posters do not even distinguish between polyurethane and nitro or between new and
40+ years old nitro finished guitars. Most of them happily lump cleaning, applying magic buffing goop or (abrasive) polishing together and I think it's kind of important to know which of those 3 to do when and why.
After reading my butt off trying to get the gist of the "what" "why" and "why not", I grew pretty reluctant to buy any "guitar care" product on recommendation of random strangers (which includes me). Since liability is not an issue for them, I consider the companies making these products "random strangers" too - none of them is happy to disclose what's in their goop and some even refuse to publish a EU safety data sheet or at least send you one if you ask them.
Why would I care that much? For example, silicone should not be applied on nitro because it will creep in every little nook and cranny (of which nitro tends to develop a lot) and cost you the one technical advantage nitro has - the easy touch-up with solvents or more nitro. Now you will find several posts that tell you the good old gold standard Dunlop 65 cleaner is safe to use on nitro because their guitars didn't burst into flames when they used that, and it came out shiny.
The US safety sheet lists only "propan-2-ol" (aka isopropyl alcohol, IPA) and "(R)-p-mentha-1,8-diene" (limonene, both solvents) as ingredients as cryptically as it gets, only the EU forces them to disclose that it also contains small amounts of polydimethylsiloxane, a silicone elastomer. Now I'm not a chemist and I never tried to touch up nitro finish and I can't tell how bad that stuff will be in practice when the guitar needs finish repairs but the point is - I don't want to find that out on
my guitar.
View attachment 31842
Now that I know what's in there I could make 3gal of that stuff for less than a single 16oz bottle!
Clouding is usually body evaporations reacting with the topmost nitro layer, turning it dull and making dirt sticking to it nicely - most educated looking posts say that you can remove that properly (elbow grease) with naphtha, which is a mild solvent deemed safe for
cured nitro. This is basically the only thing vintage guitar owners seem to agree on. But it is also still a solvent for nitro (which is why it works) and I think that any petroleum or alcohol based solvent like white spirit or diluted IPA should be applied with care and as little as possible.
View attachment 31841
Short (30s) test if 95% IPA is a good for testing nitro - guess what color the guitar is.
Re polish - my understanding after much confusing reading is that any cleaning solvent may rub off a little of the topmost, most cured nitro and "uncure" it a little, so it could be wise to wait a week before you try to apply wax. But much of the stuff everyone and their dogs try to sell you for $10/2fl oz is promising to clean and protect your finish with some magic wax
in one go to give you the stunning shine for your gear pics.
But you don't have a
new nitro finished guitar - are there dents, checking or micro cracks and do you have a way to look really close (magnifiers etc.)?
Edit: Saw your pics only now! You probably know that most if not all of the polishing goop is not transparent and works only for the little surface scratches and polish swirls. You can probably imagine how rubbing anything into little cracks or getting that underneath the finish could ruin your day. Some swear on bowling alley wax or clear carnauba wax paste and whatnot. But these waxes and may or may not highlight damages more than hiding them and some of them contain silicone again.
View attachment 31843
Fender Custom Shop cleaner for nitro guitars, would you want to rub that into finish cracks?
Abrasive polish is mostly only applicable on healthy or new finishes. It gives you fast results by deliberately removing more material, which means you can do that only so many times until you're down to the wood on thin nitro.
Even if the finish looks pretty intact because the nitro they apply since everyone gave in to the demand for it is different than the 50s stuff: I'd personally ask myself "why and when do I want to risk messing up stuff?" or "do I really want to remove the patina?". It'll come back and some people even pay hefty markups to have patina on their guitars! I'd personally avoid anything that goes beyond basic hygiene (= a very slightly moist micro fiber cloth) and rarely addressing more stubborn tarnish on a vintage guitar.
lovely Strat …
