The practice of Karung guni is common in Singapore. Its practitioners are a modern form of rag and bone men that visit residences door-to-door. They can either walk along corridors (if that particular HDB estate has a covered carpark) or for certain HDB estates where the carpark is right under the HDB blocks, walk through the carpark downstairs honking a horn. However, around landed properties, they may drive around in a lorry with a horn attached to it, instead of going door-to-door. They make visits in carts, collecting old newspapers and other unwanted items. These will be resold at specialized markets and eventually recycled or reused. "Karung guni" is a Malay phrase for gunny sack, which was used in the past to hold the newspapers. The karung guni men would haul the heavy sacks on their backs as they walked their rounds to do the collection. Today, most of them use a hand truck instead.
These people can be distinguished by their use of horns or (rarely) hand bell and shouts of "karung guni, poh zhua gu sa kor, pai leh-lio, dian si ki..." ("Rag and bone, newspapers and old clothes, spoilt radios, televisions" in Singlish and Hokkien) when making their rounds. Depending on the person, a nominal fee is paid for the quantity of newspapers or unwanted items sold.
The karung guni industry is made highly profitable due to the dense urban nature of Singapore, where hundreds of public housing Housing Development Board apartment units are located in one block, with often a dozen blocks in each housing estate. This gives the karung guni men large access to sources of scrap. There are reported stories of rag-to-riches, karung guni men who have become millionaires just from the karung guni business. Today, however, competition is usually too great.
Second-hand items in good condition bought by the karung guni men are usually resold in flea markets such as Sungei Road, though in recent times some have begun listing items additionally on online auctions. Because karung guni men are motivated by the resale value of these materials on the market, there are also reported cases where some collectors have been selective in what to receive from households, even though they may be still recyclable or reusable.
At the beginning of the 21st century, karung guni men are facing competition from government recycling initiatives and charities that directly collect from residents material to be recycled. A few karung guni men have been prosecuted for attempting to steal scrap material from the green recycling bags placed outside housing units for collection.
Changes in the industry
Since the 21st century, there has been a revival of interest in this particular industry with younger blood coming into the foray. The industry seems to be switching towards an on-demand model where convenience, incentivization and a reduction of contamination is the main focus.  Some of the websites that provide such services includes http://www.karang-guni.com, http://www.recyclingpoint.com.sg/, http://www.kgs.com and http://www.sct.sg/ where items can be recycled just with a call.
The phrase "karung guni" is often misspelt as "karang guni". This is incorrect as "karang" as in "batu karang" is the Malay word for coral, "karang" itself means "to compose", whereas "karung" means sack or bag.
- Brown A. Singapore English in a Nutshell: An Alphabetical Description of Its Features. Federal Publications, 1999. page 121.
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