Many diners take their bowls of food off the trays, as it can be difficult to eat with the trays on the table, due to space constraints, or the instability of the tray bottoms.

Many cleaners are then quick to collect the trays while diners are still eating ("Reward those who return their trays" by Mr Seah Yam Meng; Wednesday).

There seems to be insufficient trays, and cleaners have been instructed to promptly collect and return the trays to the vendors for re-use.

More trays should be purchased for vendors at hawker centres. The trays should bear a printed slogan: "Please return plates and bowls with this tray."

I have also seen cleaners telling off patrons who try to return trays to them instead of to the tray-return stations. Perhaps they could be trained to be more polite.

Students in schools return their used plates and bowls because they are monitored closely by teachers and student leaders ("Practice must extend beyond school canteen" by Ms Oei Khoen Hwa; Wednesday).

Peer pressure is also a positive factor.

Schools teach students to "clean up after I use". But it seems that they forget this once they leave the school, and it becomes "clean up before I use".

Parents must also do their part when they dine at hawker centres and foodcourts with their children.

Announcements to remind diners to return trays are ineffective. There must be a personal touch.

Maybe schools could deploy older secondary students to hawker centres during school holidays to help persuade diners to return their trays. This could be part of the students' community service.

Lim Jit Chaing