CD Disc Surface Cleaning with Oolong Tea!? — A Little Experiment

【Recommended Ultrasonic Cleaner Usage Reports】
Part 1｜Part 2｜Part 3｜GT SONIC｜Oolong Tea

Once again, this is a topic I, the perpetual ghost member who only ever lurks, picked up from the Phile-web community. Over in the comments section of Hakoniwa Pure Audio, someone brought up the idea that cleaning CDs with oolong tea improves the sound quality!? — so I decided to give it a go straight away and see what it was all about. The original article written by Silurian-san is linked below.

Having stepped on every landmine imaginable over the years with various CD cleaners and “sound-improving?” coating agents and the like, I find myself somehow unable to resist getting involved whenever this sort of topic comes up — ahem. And so, in that same spirit, I’d like to put things to the test once more.

Below Is a Summary of the AUDIO STYLE Comments Section

25. Posted by Mogu
Hello. I spotted an article on Phile-web about cleaning CDs with oolong tea improving sound quality, and I couldn’t help but react to it. I’m thinking of giving it a try. In your cotton swab article, I noticed you avoided chitosan swabs — what do you think of the idea of soaking a tissue in oolong tea and using it to wipe away dirt from a CD? I’ve also been thinking an ultrasonic cleaner might be nice, but cost-wise, the oolong tea approach does seem appealing. It’s simple, too. Cheap and easy. I suppose I am a little concerned about residue left behind by the oolong tea, though.

26. Posted by pastel_piano
Hello, Mogu-san.

>>What do you think of the idea of soaking a tissue in oolong tea and using it to wipe away dirt from a CD?

I had a look at the article in question. First of all, I think the sound will appear to change no matter what you use — oolong tea, green tea, mineral water, plain tap water, washing-up liquid, alcohol, anything. Whether that change is for the better is entirely subjective, so if it suits your taste, then by all means give it a go at your own risk.

It seems unlikely that oolong tea contains anything that would cause serious harm to polycarbonate, but speaking for my own preferences — whether it’s equipment terminals, CDs, or any other component — applying something that leaves residue behind goes against my personal principles. Even if there is an audibly favourable effect in the short term. And if you use a tissue, you’ll also be leaving behind a considerable amount of fine paper fibre. Even if a factory-pressed CD has traces of machine oil or similar on it, I would think the microscopic contamination introduced by wiping it — despite one’s best intentions — far exceeds that, so nothing should beat a brand-new disc straight out of its wrapping for sheer cleanliness.

With that said, what personally interests me most is the ultrasonic cleaner you mentioned. Among those, the Sanwa Direct 200-CD037 (formerly TOSHIBA TKS-200/TKS-210) looks particularly handy since it comes with a dedicated stand for cleaning CDs and DVDs. I’ve actually been going back and forth about buying one since spring. That said, there’s still the rather significant problem of how to dry the disc afterwards without scratching it — would a fan work, I wonder?

……Well, there’s no point getting too neurotic about it all, so let’s just treat it as a bit of fun.

27. Posted by Mogu
You’re right, I do have reservations about wiping after cleaning. I suppose dirt will find its way on regardless, unless you’re working in a clean room, so perhaps there’s no need to be overly fussy about it. The Toshiba ultrasonic cleaner — what about using a hair dryer on the cool setting to dry the disc? I hadn’t really looked at Phile-web much before, but everyone there is sharing all sorts of interesting ideas. It’s quite fun. Aside from the oolong tea, there’s apparently someone who wrapped charcoal sheets from the 100-yen shop around their power cables and got better sound. I’m the type who tends to jump at low-cost ideas, to be honest. I know the sensible thing is to research and buy proper accessories, but somehow I ended up at the 100-yen shop again today. I’ve already wrapped the charcoal sheets around the power cables of my CD player, amplifier, and PS3, and I’m seeing how it goes. P.S. I tried the oolong tea CD cleaning on just one disc. It did seem to sound better somehow…

28. Posted by Nakata
Oolong tea is known for dissolving grease — there’s even a tip about using it as windscreen washer fluid (though you’d have to use it before it goes off, otherwise it’s a disaster) — so academically speaking, there is a certain logic to it. The real issue, though, is that the transport jitter really shouldn’t be leaping across to the DAC like that…

*********************Thank You for the Comments*********************

Cleaning CD Disc Surfaces with Oolong Tea — Plus a Comparison with Neutral Detergent

First, regarding oolong tea — as Nakata-san mentioned, it apparently has the effect of lifting oil films from glass surfaces and the like. You can sort of sense this from the dry, almost astringent feeling you get when the liquid touches your hands. It’s probably not as powerful a degreaser as a surfactant-based cleaner, but by that same token, it may well be gentler on disc surfaces and on the body than some of the harsher chemical cleaners out there.

Well, it costs nothing and there’s no harm in trying — so I opened a two-litre PET bottle of oolong tea (Itoen, 2L) that happened to be in the house, and soaked some soft Silcot — a high-quality cosmetic tissue (to avoid scratching the disc surface) — with it. The reason for Itoen rather than anything else is simply that it was the cheapest option. Suntory’s oolong tea might well produce better sound — after all, they do have Suntory Hall.

When I soak the Silcot with the oolong tea, it turns quite a deep brown. The disc surface won’t actually be stained by this, but at the microscopic level there does seem to be a fair amount of residue… It might affect reflectivity by a fraction of a percent or so. CDs that have developed a whitish oil film from sitting unused for a long time, or ones with mould and other grime on them, will come up looking pristine after a wipe with this. ※Just to be clear, though — wiping with tap water will also produce the same result.

The CDs I treated were classical discs on the London label, purchased in the late 1980s — Ashkenazy’s Mozart piano concertos, and Radu Lupu’s Beethoven piano sonatas. Since I have import box sets containing the same recordings, these are essentially duplicate copies where it wouldn’t be too painful if something went wrong. Both are superb performances and essential listening for any classical music devotee. Over the course of twenty-odd years, they had been cleaned several times each with whatever CD cleaning fluid was available at the time. My earlier article on the LEIQUA Balance Washer is linked below.

After leaving the discs on the shelf for a while (with a clearly visible white oil film on the surface) and listening through them casually, I cleaned them with oolong tea soaked into a Silcot as described above. Alternatively, I first cleaned them with neutral detergent and tap water, listened through them, and then treated them again with the oolong tea.

I tried blowing the water droplets off the disc surface with a fan, but they just wouldn’t budge… In the end, waiting for natural evaporation was too much trouble, so I went ahead and gently wiped them dry with a Silcot as usual. Cosmetic cotton pads are highly recommended for this — they don’t scratch the disc surface at all, and cause far fewer scratches than certain expensive dedicated CD-wiping cloths. Having gone through all of that, I played back the same track and had a listen.

It goes without saying that CDs cleaned by any method will sound clearer than ones coated in an oil film or airborne mould — but the real question is how the oolong-tea-cleaned disc compares to one washed with neutral detergent (washing-up liquid containing surfactants) diluted in tap water. The oolong-tea-cleaned disc had a subtly different character — a quieter, more subdued quality, with less of a sense of distortion. It might suit CDs with a harsh, digitally-edged top end… On the other hand, there was a feeling — perhaps — that the sense of reverberation and the way the sound lingered in the air had diminished slightly, and the tonal colour seemed just a touch duller. That’s roughly the extent of the difference.

My go-to is Ecover Zero, a Belgian-made, fragrance-free, colourless, mildly acidic washing-up liquid

Not quite satisfied, I re-washed the oolong-tea-treated CDs under running tap water with a neutral kitchen detergent (surfactant-based) and a urethane sponge, and had another listen — and to my ear, the neutral detergent gave a fresher, more natural sound with less colouration than the oolong tea treatment. Of course, whether diluted neutral detergent will have any long-term effect on the disc surface is hard to say, so I can’t recommend it without reservation — but in terms of sheer cleanliness, it should come out ahead.

～ Summary ～

Even with the various liquids I’ve applied to CD surfaces over the years, while the sound has sometimes shifted in a subtle way, there haven’t actually been many instances where I’d say it genuinely improved — and oolong tea feels like more of the same, really. Depending on the disc, depending on the system, it might just click for someone… It’s certainly far better than the oil-based CD cleaners that used to be sold here and there some years back — but then again, oil-based coatings, even those marketed specifically for CD and DVD use, can soften or otherwise damage the polycarbonate surface, so I would strongly advise against using them.

As I also wrote in the comments above, when it comes to personal preference — whether it’s CD surfaces, vinyl records, or various terminals — leaving no residue behind, adding nothing at all after cleaning, is probably the best approach in the long run. I myself have a CD collection running well into the thousands and beyond any sensible count, and depending on where they’ve been stored, some have developed a whitish film, or even — I must confess — proper mould with what look like little legs growing on them (tears). For cleaning old, dirty CDs like those properly, I do think the best approach is to use an ultrasonic cleaner with a small amount of surfactant added to warm water. The microscopic cleaning power of an ultrasonic cleaner is something else entirely, and since it’s essentially just water (warm water), it should be gentle on the discs too — and it comes highly recommended over at PLUTON-san’s site as well. With all that in mind, I’m planning to pick up the TOSHIBA TKS-200 before the year is out. ⇒TOSHIBA TKS-200 Ultrasonic Cleaner Purchase Review

Either way, the fact that such a tiny difference in disc surface reflectivity can have this much audible impact says rather a lot about the rather sorry state of the CD format and its real-time S/PDIF digital transfer standard — it really is quite dismal when you think about it. I find myself in full and fervent agreement with the comment that the transport jitter really shouldn’t be leaping across to the DAC like that… When you get right down to it, with hi-res download files — where there is no physical container to begin with — perhaps one could be freed from this sort of absurd predicament. ⇐ Though of course, that brings its own entirely separate set of problems, one after another…

【Recommended Ultrasonic Cleaner Usage Reports】
Part 1｜Part 2｜Part 3｜GT SONIC｜Oolong Tea