Mrsg (Jupiter, Fl, USA) on 06/13/2013
Deirdre (Atlanta, GA) on 01/07/2009
Jinny (Sydney, NSW Australia) on 07/17/2006
Liliana (Pembroke Pines, FL) on 03/01/2004
Mayeast (Las Vegas) on 05/27/2006
Elaine (Chicagoland, Illinois) on 04/24/2007
Shirley (mid-west, Missouri) on 07/21/2007
A word of caution, vinegar can remove the enamel from their teeth, the same as it does for people. I have always added 1/8th teaspoon of baking soda to one-teaspoon vinegar before I add it to their water. Let the vinegar/baking soda mix sit until the fizz stops then add it to the water.
I could have missed it but I didn't see anyone saying they were doing that mix. We don't want to fix one problem while causing another.