In order to check whether your water is hard fill a clean empty plastic bottle about halfway with water. (fullhealthsecrets.com)
Or make some simple with empty plastic bottles filled with some small bells and uncooked rice or buttons. (fixnation.org)
It is only after viewing Frazier's photographs inside the gallery that a visitor discovers that the residents of Flint, Michigan, used empty plastic bottles to express the stated message. (contemporaryand.com)