In The UK There Is A Saying,

'where there's muck there's brass',

meaning that items worth money could be found in rubbish, and it certainly seems that way in Switzerland, where the population it has been estimated flush away over $1.8 million of gold that passes through the country's wastewater each year, not to mention another $1.7 million or so in silver! the study can be found here, but for a simplified overview this is an easier read, the trace metals appear to be the valuable remains of Switzerland's watchmaking and gold refining industries, according to Alanna Petroff of CNN, it appears that roughly 70 percent of the world's gold makes its way through Swiss refineries each year, so at the weekend down to the sewage treatment plants and out with the metal detectors, 'where there's muck there's brass' indeed there is.