IT'S time once again for us concerned citizens to march to Central carrying balloons. But if you are joining in, please leave your plastic bags at home. Mother Earth's band of troubleshooters - Friends of the Earth - thinks it's time to wage war against supermarkets and retailers who heap plastic bags on us. FoE's Maria Villamil says: ''Even after one year of the BYOB [Bring Your Own Bag] campaign the number of discarded plastic bags is not diminishing.'' So at noon on Saturday, they are organising a protest march to the Legco (assembly point Chater Garden), before calling at a Park'N Shop and Wellcome supermarket in the area. And while the eco-adrenalin is still flowing, you might like to join the international beach cleanup at Shek O on September 19, when Miss Hong Kong will be going along to dirty her hands for the cause. While Maria was at it, she also reminded Keeping Posted of another mega event - Jog For The Earth - coming up soon. But for more info on this, and the aforementioned dates, we suggest you call Maria or Janice Cates on 528-5588.