If our target population is elder people, maybe we could try to use some images or songs which makes them feel familiar.
For example, the Beatles!
Use some image combining with lovely song, like"help!", may encourage them to increase recycle.
(source:http://www.milwaukeerecycles.com/;http://fc04.deviantart.net/fs49/f/2009/188/9/6/The_Beatles_wallpaper_by_monsieurvoitures.jpg;http://www.eriefamilyhealth.org/wp-content/uploads/2010/08/recycle-bins.jpg)