In reply to Jomitch:
The classic answer (I think from Petzl originally) for Ecrin Rocks was to use them as hanging baskets for some nice flowers!
I don't know but doubt the plastic is the type that can be reused. Some things do genuinely just end up in landfill unfortunately. If you've got little kids or know someone who has, a dressing up box is another reuse idea! A couple of my old helmets ended up in the dressing up box and the grandparents' for years, my kids and my sisters' kids all seemed to enjoy wearing them along with old curtains as a cape etc.