They have so little value that most shops will not take them and banks charge a handling fee for accepting them.
But the 10, 20 and 50 cent coins lying round in jars, bowls and moneyboxes in Hong Kong homes could add up to as much as HK$100 million, according to one estimate.
This has emerged from a survey by the Democratic Alliance for the Betterment and Progress of Hong Kong in which 70 per cent of respondents said sellers and service providers had refused to accept the coins from them.
'Many stalls at the wet market will not accept small coins,' said retiree Tsui Juen-tai, 73. 'Sometimes we even get scolded by stall owners for trying to use them.'
People said that as it was difficult to use the coins, they stored them up, and based on the response the DAB estimates there could be HK$50 million to HK$100 million worth of coins lying unused.
More than 70 per cent of the 1,030 respondents interviewed in the survey last month - half of them aged over 50 - said they stored the coins.
'It is unacceptable that shops and public transport reject even a small number of small coins,' said DAB lawmaker Chan Kam-lam, who oversaw the survey.