Since goldrush days San Francisco has been a magnet for those on the make. But the latest moneymakers aren't interested in striking gold, they're in search of cans and bottles. The city's efforts to boost recycling rates have been so successful that the value of rubbish has spiralled, leading to battles between official, unofficial and downright criminal garbage collectors.

San Francisco now recycles 78% of it's trash: paper, bottles, cans, plastics and even food gets recycled or composted. This is partly due to the California Bottle Bill of 1987 that introduced legislation to ensure a deposit was repaid on bottles and cans that were sold in the state. The amount recyclers get depends on the package they return.

The city has also made it extremely easy for residents to recycle. They now have three bins. A brown bin for food waste, a black bin for general waste and a blue bin for recycling.

It's these now iconic blue bins that scavengers target, pillaging the bottles and cans before Recology, the city's official garbage collectors, can get to them. They then take the booty to recycling centers and collect a few bucks.

The fear is that now small time pilfering by a handful of scavengers is becoming more organised with criminal gangs getting in on the act.

Tom Heap hits the streets of San Francisco to meet those making cash from trash.

Producer: Martin Poyntz-Roberts.