They wanna put me in the ultrasonic and I say "no, no, no!"
Why I don’t recommend using Ultrasonic Cleaners
Now this is going to be controversial, but I stand by it. And no, I am not anti-“Big Ultrasonic” and think they will take over the world. We’ve all seen those cheap little ultrasonic cleaners promising “professional cleaning results in 3 minutes” and that they can “restore the perfect shine of your jewellery items at home”. Heck some jewellers even sell them! Just use the special solution or even plain tap water; I mean that won’t hurt anything right? Wrong.
My problem is that you can permanently and irreparably damage your jewellery if you aren’t 100% sure it can be cleaned in an ultrasonic cleaner.
So what is ultrasonic cleaning?
Ultrasonic cleaning uses a process called cavitation which involves creating micro bubbles in a liquid. In the machine there is a transducer which creates high frequency sound waves (most jewellery cleaners use 40kHz) and these waves go through the liquid. This creates those micro bubbles that implode as fast as they are made which also generates pressure and heat (remember this for later on). This combination of pressure, heat and velocity of the bubbles is the reason ultrasonic cleaning can get into every part of a piece to dislodge dirt and other particles.
Then there is the cleaning solution. While some makers say you can just use water, they will of course offer their wonder cleaning solution. Most of the time this is usually just some form of soap, but they can often contain ammonia which is caustic (which even people who recommend using ammonia for cleaning jewellery admit that its caustic properties will cause your jewellery to wear with repeated cleaning).
In making it look ‘so easy’ and ‘totally safe’, sellers of ultrasonic cleaners tend to gloss over the fine print of all the things you should never clean with it.
What’s the big problem then?
My problem is that you can permanently and irreparably damage your jewellery if you aren’t 100% sure it can be cleaned in an ultrasonic cleaner. The Gemmological Institute of America (GIA) even mention getting a stone report before cleaning a stone in an ultrasonic cleaner.
In making it look ‘so easy’ and ‘totally safe’, sellers of ultrasonic cleaners tend to gloss over the fine print of all the things you should never clean with it. Let’s look at them shall we?
They say to use the ultrasonic and I say ‘no, no, no!’
Treated stones such as Turquoise, Lapis Lazuli, Malachite, Onyx, Amber, Coral & Agates
Some of these stones are fragile and under the heat and pressure of an ultrasonic cleaner, they can end up breaking. Also, many of these stones are treated or dyed to enhance their colour and putting them in an ultrasonic will make them dull.
Stones susceptible to changes in heat and temperature – Sunstone, Moonstone, Fluorite, Iolite and Kunzite.
Whether these have been treated or not, these stones are sensitive to changes in heat and cleaning in an ultrasonic can cause them to crack.
Pearls whether freshwater, dyed or mother of pearl
These gems of nature can easily break or sustain damage to the nacre by ultrasonic cleaning. This is especially true for mother of pearl which is soft and some cleaning solutions can even partially dissolve the outer layers.
Opals – of any kind and especially doublets or triplets.
A solid opal is already a brittle stone and the high pressure and temperature made by the ultrasonic can cause them to fracture. If you’ve got a doublet or triplet opal (which is a small slice of opal glued to a backing), the glue can readily dissolve and it’s not really a salvage job.
Emeralds
Emeralds are a brittle stone (some jewellers are even scared to set them in bezels) and a lot of emeralds (some estimate up to 90%) are usually treated with oil. OIL? Yes – oil. You see, emeralds tend to have inclusions, so they are often oiled to fill those inclusions and improve their appearance (vibrant green and clear). Guess what the amazing cleaning power of an ultrasonic does? It removes that oil and leaves you with an ugly, fractured emerald.
An emerald before (left) and after (right) ultrasonic cleaning, see the cloudiness? Credit Gemmological Institute of America (GIA) (https://bit.ly/3bCxOSF)
Tanzanite
Many tanzanites have been heat treated to enhance their colour and popping them in your ultrasonic can end up leaving them looking bleached plus being very soft (you guessed it), they can crack or fracture with the heat and pressure created.
Any stone with large inclusions, feathering or cracking
This one is a given. Any stone that has a weak point which is exposed to heat and pressure runs the risk of fracturing or cracking.
Diamonds
Yeah well what about Diamonds huh? Not if they are coloured you don’t and maybe not even if they aren’t.
Coloured diamonds (blue, yellow, cognac etc.) are heat treated to bring out their beautiful colour and ultrasonic cleaning may cause them to dim and fade over time. White diamonds? This depends. Some cheaper diamonds can be ‘fracture filled’ to improve their appearance and this filler can dissolve in an ultrasonic leaving them looking shabby. The second issue is if an ultrasonic cleaning solution contains bleach, the chlorine can over time yellow the diamond.
A fracture-filled diamond that has cracked in an ultrasonic cleaner. Image – Credit GIA (https://bit.ly/3bCxOSF)
So as you can see, my problem with ultrasonics is less about how they work and more about what can happen when you take that turquoise piece you love or something sentimental like a generations old emerald ring or a strand of pearls and have them ruined.
Hope is not lost – how to safely clean your jewellery
I’m going to use the fabric care classification of stones to help you on your way
The Delicates
Pearls & Opals (including doublets and triplets)
Now full-on pearl care is another post entirely, but the basic principles are the same for both opals and pearls. Never immerse them in water. If they have dirt on them – don’t just wipe it with a dry cloth. Why? Turns out some household dust can be up to 7 on the Mohs scale (a measure of gem and mineral hardness from 1 to 10) and as solid opals and pearls are softer, they can get scratched.
Instead, get some lukewarm water (never hot, I’m talking mid 30 degrees here) with a drop of gentle soap (mild dish soap please – not the ultra-strength concentrated power clean stuff), another bowl with plain lukewarm water and a soft microfibre cloth. Dip one corner of the cloth in the soapy water and wipe them very carefully. If you see any lodged dirt in settings or on the thread, use a toothpick to very carefully dislodge it. Use another corner of the cloth dipped in the plain water to clean the piece and remove any soap residue. Then use the dry part of your cloth to dry it immediately and thoroughly. Patience is the key to a good result here.
The Sensitives
Emeralds, Tanzanites and Soft stones (Turquoise, Lapis, Amber etc.)
Like above, get some lukewarm water (still the 30-40 degree mark) with a drop of gentle soap (yes still the mild stuff), another bowl with plain lukewarm water and a soft microfibre cloth. This time you will also need a very soft toothbrush (no, not one with fancy rubber bits, charcoal infused and twelve directions of bristles – basic soft plain toothbrush).
Using the soapy water and brush and working over the bowl, carefully brush around the stone and setting taking special care around any prongs, settings and filigree work. Again careful use of a toothpick can dislodge dirt accumulation. Wipe over with a part of the microfiber cloth dipped in plain water and dry with a soft microfibre cloth.
The Regulars and plain metals
Most remaining gemstones and metals (gold, silver, platinum).
Same as above, microfibre cloth, soft toothbrush, warm clear water and a bowl with warm water and yes finally, you can use a drop or two of your Dawn or Fairy or Morning Fresh. This time you can let the piece sit in the water for a couple of minutes to soften the dirt and then working over the bowl, brush carefully to remove dirt (again watch the prongs and filigree work). You can dip the piece back in to remove what you’ve brushed off and keep brushing until clean. Rinse in the plain warm water and then dry carefully with a soft microfibre cloth.
Why the bowl? Indiana Jones and the Curse of the Lost Stone.
Sometimes by dislodging some built up crud around a bezel or prong or if you’ve been a bit vigorous with the toothbrush, a side stone like a small round diamond might fall out because the dirt was keeping it in place! So once your piece is clean and before you throw the water away, check it to see if everything is still in place. If something is missing, you can go fishing in the bowl to recover a lost stone to have it re-set rather than having it go down the drain.
What about jewellery cleaning products?
If you are worried about making the solution at home, there are jewellery cleaning solutions out there but please check with the store to make sure it is suitable for the jewellery you want to clean.
What if I still can’t get it clean or want a deeper clean?
As independent jewellers, we will clean any piece of jewellery and I always like to see one of our pieces come in for cleaning
In that case, I would recommend taking it to a reputable jeweller to have it professionally cleaned. Note that some chain jewellers will offer a cleaning service for their pieces. As independent jewellers, we will clean any piece of jewellery and I always like to see one of our pieces come in for cleaning and we will recheck it for free as well. Jewellers can either manually, steam or funnily enough, use an ultrasonic cleaner! The difference is that a reputable jeweller will check over the piece carefully, identify the stones and how they can be cleaned and check both the settings and stones under magnification before using any kind of steam or ultrasonic cleaner.
OK fine, but I really really really want to use my ultrasonic because it’s cool – is there anything I can put in it?
If you really want to clean something, you can put plain gold or plain silver pieces in them, so plain solid gold or silver chains, plain solid bangles, plain solid earrings (with no stones) and plain solid rings (no stones). Read the instructions that came with your ultrasonic jewellery cleaner carefully and follow them. As in what to use, use jewellery safe solution (I find Town Talk good for this) but the safest bet will be plain de-mineralised water.
I know I’m probably going to get a lot of flak from the ultrasonic die-hards who think I’m being over-cautious however jewellery is sentimental and to have its story taken away by a $50 machine just isn’t worth it for me.
