The San Francisco Mint Burned Its Carpets to Find $3,200 Worth of Gold

Even after the gold fever died down, gold itself was in the air in San Francisco—as long as you knew where to look. That place would be in the San Francisco Mint. In a majestic granite and sandstone building downtown, bullion was turned into gold coins—as well as lots and lots of gold dust.

A fascinating 1893 newspaper tour of the San Francisco Mint—spotted by historian Yoni Appelbaum spotted on Twitter—takes us into the workrooms where men cut gold into strips and the adjusting rooms where ladies filed coins down to just the right size. Millions in precious metal passed through these rooms every year, and none of it went to waste, recovered, instead, through "seemingly small economies." This included setting fire to the carpets to find any gold dust trapped within:

The floors of the workrooms are covered with perforated iron flooring in small sections. Every night these sections are removed and the floor swept. The sweepings are then worked over with acid, and the yield in gold and silver amounts to $6,000 per annum. Once a year every truck about the building is burned, irrespective of its condition, and also the clothing worn in some of the workrooms, that not a particle of the previous metals may be lost. Once in four years the carpets of the adjusting room are burned. The last burning enriched the United States coffers to the extent of $3,200.

That's $3,200 in 1892 dollars, mind you. The article doesn't mention how many ounces of gold were recovered from the carpets, but a 1886 annual report by the director of the mint notes 171.672 standard ounces in that year's burning. At today's gold prices and in today's dollars, that over $200,000. In dust.


Gold coins are pretty much collector's items rather than real currency now, but gold dust is still every bit as valuable. Today, jewelers will recover the tiny bits of gold from polishing dust, too. A pound of polishing dust can yield up to an ounce of gold. Here are instructions for how one might recover gold with some lye, alcohol, a stainless steel pot, and a stack of casserole dishes. When the price is right, we'll go anywhere looking for gold. [via Yoni Appelbaum]