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Our Refining Process for Polishing Sweeps

Sometimes, a jeweler will visit our storefront to drop off some scrap, and they are surprised to learn that polishing sweeps are one of the many types of materials we will buy. They return with a small baggie filled with this crud from their workbench (or in one case, the old carpeting from the work room) and wonder aloud “how are you going to get gold out of that?”
The answer is: very carefully, through a complex series of steps. Polishing sweeps contain gold, but also less valuable metals, wax, buffing wheel fibers, jewelers rouge, buffing compound, dirt, and other waste materials. The process for extracting gold and platinum from your polishing sweeps can be generalized in the following steps:

Step 1 – Polishing sweeps (or a carpet containing them) is incinerated until all combustible waste is completely burned away.

Step 2 – After a thorough incineration, the leftover material is pulverized into a fine powder. This involves putting the  material into a large drum that has very heavy balls in them. When the drum rotates at a high speed, it pulverizes everything inside.

Step 3 – The pulverized powder is separated into two different types of material: fine powder and the coarse material.

Step 4 – The fine powder is assayed.

Step 5 – The coarse material is to difficult to assay because it’s not uniform. We run a magnet through this lot before we melt it to extract magnetic material. We then melt the coarse material into a bar.

Step 6 – Assay the bar that was melted from the coarse material.

Of course, all of these steps take time to get the exact amount. Unfortunately, we can’t offer our usual same-day payout for polishing sweeps – we have no idea how much to pay you until we reach that final step. The good news is, MGS now processes polishing sweeps faster than ever before! In just two weeks, we can have your assay results and payout ready.

And that’s not the only service we can do faster. For large lots containing gemstones, we can safely remove the gems via a chemical process and have your payout ready in only 5-10 business days. If you have any questions about either process, please don’t hesitate to contact us


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