I USED to buy Eco friendly washing up liquid in gallon containers from a man very much into conservation. He had the containers back, filled them with water and placed in his greenhouse.

He said they warmed up during the day, the heat from which kept the temperature up at night.

Pity we can't have something to make use of heat from the many hot cars which stand outside all day.

Maybe mini greenhouses, or produce power to help run the cars!

MRS H READ, Highcliffe.