I I'm not sure we have that facilty in the UK yet, but although deposite returns were discussed on the radio recently, we did have a deposite system 50 years ago when we could get 3 or 4 old pennies on lemonade and beer bottles. I would suggest a good look at tag info here for other countries.
http://wiki.openstreetmap.org/wiki/TagFinderhttp://wiki.openstreetmap.org/wiki/TagFinder
and as you suggest debating a new tag which is fit for purpose. The plastic bag tax seems to be working and i think returnable deposites would be a good idea as well.
