Keep a diary for 3 weeks of the things that the Cubs have recycled - they shoudl work hard to try and improve the amount of stuff that they recycle, possibly with a prize for the top Cubs.
1x Sheet of card per Cub
1x pencil per Cub
1x 30cms string per Cub
Box of colouring crayons pencils and pens to decorate.
Make a grid like the one shown in the picture attached and talk about all the different things that Cubs can recycle (put these things in the columns across the top). Attach the pencil to the card with selotpae and string (the idea is to make sure that there is always a pencil attached to the sheet so there's no excuse for not recording the stuff they recycle).
They take it home and put it by their recycling boxes, when it comes back they should show and improvement in the number of things recycled.