for those who buy orange juice, buy the kind in the plastic bottle carafe'. (not with the green cap!)after you open the bottle,there is an orange ring still left on it, pry it off(comes off easily ) throw to cat, and let them enjoy

It is bigger than a milk ring so I think it is much safer

PS. also if you buy planters sunflower seeds in a glass jar you can get the same kind of ring as the orange juice ring....but it is a yellow ring

see sample of fun below