Given their penchant for abiding by rules, they are likely to follow directions for cleaning up, especially in an environment where everyone else is doing the same, say experts.

Clear signals are the key to conversion.

'Perhaps there should not be a back-up team of cleaners to clear up the mess after diners, or they will think it's acceptable to leave the table and the mess,' she said.

The Straits Times is launching an effort to encourage diners to return their trays, with posters, stickers and hanging mobiles serving as reminders at five Kopitiam outlets islandwide.

The common sight of uncleared trays at foodcourts is not just an eyesore, but also points to the need for Singaporeans to brush up on their social graces.

Indeed, Prime Minister Lee Hsien Loong pointed out at this year's National Day Rally that improving in such areas was important because the well-being of Singaporeans depended not just on bread-and-butter issues but also on how people behaved and related to one another.

Agreeing, Prof Straughan said Singaporeans must be active stakeholders.

'If you see someone walk off, call them back to let them know what the expectations are. It is only through active social policing that we can encourage non-conformists to play their part,' she said.

To make tray clearing a breeze, clearly visible stations should be manned to ensure they are clean, and that there is always space for used utensils. Sinks around the collection stations also make it more convenient for patrons to clean up after.

Prof Straughan cited a foodcourt in Tokyo Disneyland as a model of such an environment.

'There is a large return station with clear indicators of which utensils should go to which area.

'There are also sinks and wipes, so that when you are done clearing your tray, you can rinse off and dry your hands. Everyone was doing it, and the cleaners were there to clear the collection area and clean the tables,' she said.

Banker and foodcourt regular Nicolas Chong suggested that instructions be spelt out to a T: 'If there are bold signs telling people to return their trays to the designated stations, I'm sure they will.'

Repeating the action will turn it into a habit - and a good one at that.

Dr Ng Beng Yeong, head of psychiatry at the Singapore General Hospital, said: 'Over time, performing the task will become second nature.'

Although some blame the traditional preference for communal dining for creating messy tables, regular foodcourt diners say that is no excuse.

Said retired teacher Esther Wong: 'Many of us clear our plates after a meal with the family at home.

'I don't see why it should be any different when we share food at a hawker centre or a foodcourt.'

But to truly make Singaporeans gracious, the effort must be sustained by individuals.

To change mindsets, it is important to create a culture that encourages cleanliness, said consultant psychiatrist Adrian Wang.

A campaign, such as The Straits Times' Goodness Gracious Me! effort, would show only short-term results if not backed by a long-term strategy, he added. 'Old habits die hard.'

To improve overall social graces, 'we need to start young'. That means setting an example for children. 'Kids mirror adults. That's why we need to behave well before we can teach our kids manners.'

juditht@sph.com.sg