Saving Precious Stones from the Plumber’s Wrench

A recent question from an amateur jeweller is the inspiration behind this post.

The questions are

‘How to stop precious gems and small jewellery going down the sink?’


‘How to find diamonds at the bottom of a dirty ultrasonic cleaning tank?’

As a diamond setter, each and every time we set a stone the final test is to run it through the ultrasonic cleaner.  Naturally, this cleans the setting nicely before presenting it to the customer, but since it also  gives the setting a serious workout, for us it also serves as a practical test of how securely the stone has been set.  We often clean settings in the ultrasonic cleaner before working on a new job, so we can have a real good look at the piece before we start.

Every now and then the ultrasonic cleaner will loosen dirt which turns out to be the only thing that was holding a stone in place in its old setting – and the setting and stone will part company.  If that happens at the start of the day, when the cleaner’s tank is still pretty clean, it’s a very simple task to find the stray stone.  But after a big day, with lots of gunk floating about in the tank, it can be a major search and rescue operation.  What’s more, fishing inside a really dirty tank is not our idea of fun.

It’s worse, of course, to empty the tank, only to discover, too late, that the stone has gone down the drain.  The embarrassment of calling in the plumber will only be slightly less than telling the customer you’ve lost their diamond.  Clearly, these are situations we would all prefer to do without.

Avoiding the Loose Stone Scenario

Here’s how to avoid the problem in the first place:

  1. Place suspect pieces inside a small vegetable sieve.  Most kitchens have such items in a bottom drawer – the cheap plastic style with nylon weave is perfect.  HINT. If you don’t have a sieve an old lady’s stocking will do fine – just tie a knot in one end to hold the piece secure.
  2. Put the sieve, with setting/stone, inside the basket and run through cleaning cycle as required.  At the end of cleaning cycle remove the sieve and make sure the setting and stone are intact.  If the stone has come loose then at least it has been contained in the sieve and you can have it reset.  NB Do not heat the tank  – if you notice the sieve getting floppy, remove it promptly.
  3. If you forget to use a sieve, just make sure you do not dump the tank water without checking you have the stones first.  If you do lose a stone in the cruddy tank water, do not despair – read the hint below.

Finding and Retrieving Lost Treasure

OK.  You now have a clean setting, but it’s missing an expensive stone which you need to find before the owner comes to collect it.  Here’s the procedure:

  1. Do not dump the tank water.
  2. Apparatus: You will need to acquire two items:
    1. a large glass (see through) jar or bottle
    2. a big blob of bluetack
  3. Switch off power to the ultrasonic cleaner at the unit and at the powerpoint.  Detach lead from machine.  NB If water level is high you may have to remove some from the top – you will be inserting the jar or bottle, which will displace some water.  You don’t want spills from water going over the side of the tank.  HINT.  If you do need to remove water, drain from the top of the tank to minimise risk of scooping up the stone you are searching for.  Before dumping this water we would recommend pouring it through a fine weave sieve as well.  Check that the stone is not in the sieve before going any further.
  4. Firmly attach the blob of bluetack to the bottom of the jar or bottle.  Remove the basket from the unit.
  5. Carefully push the jar or bottle towards the bottom of the tank.  As the object goes deeper into the water, most of the crud will simply move away.  Through the glass bottom you will be able to examine the bottom of the tank for any objects that have fallen.
  6. Once the stone is found, steadily press the bluetack blob into the stone until it is firmly held against the glass base.  Then carefully remove the stone from the water.  Your salvage operation is now complete.
Liquid Glass Oz designs quality ultrasonic cleaners for commercial operations in Australia and New Zealand (N18973)