By Catherine Haug, Feb 2015
Thanks to K. Britton for this useful hint. See also her related Kitchen Hint for Pet Urine on Carpets.
I started using the Dawn/vinegar combination when my granddaughter informed me that nothing beat window washing like a Dawn-in-dishwater-strength concentration wiped onto windows and wiped off with a janatorial-grade black squeegee.
I also use Dawn-vinegar solution on bathroom surfaces such as the window, show glass and mirror, to remove calcium spots. No rinsing is needed. Works fabulously! The good squeegee is important; cheap ones streak.
Cat’s notes about vinegar and dishwashing liquid
I use just apple cider vinegar (ACV) and water in a spray bottle, and spray it on my bathroom tile, window and mirror after taking a shower (no dishwashing liquid like Dawn added) to keep those surfaces free of calcium spots and soap scum. I also use it as a hair rinse after shampooing as it removes soapy residue, restores the protective acid mantle of scalp and hair, and helps prevent dandruff. See Kitchen Hints: Uses for vinegar for more.
Dawn dishwashing liquid (or other dishwashing liquid) added to the vinegar water may improve the cleaning ability of the solution, but its main contribution is that, as a detergent, it does not form soap scum and, along with the vinegar, helps to keep soap scum at bay.
However, dishwashing liquids (except those that are real soap, such as Dr. Bronner’s) contain many toxic ingredients such as parabens that are known to be cancerogenic, and preservatives. Without preservatives they would encourage the proliferation of bacteria and molds.
Real soap, on the other hand, is naturally antibacterial and antifungal and does not need added preservatives. There are many homemakers in the Flathead who make natural soaps for sale at Farmers Markets. Or you can make your own; see Gathering Summary: Making Soap at Home, by Kathy Mansfield, January 26, 2011 and Gathering Summary: Rendering Animal Fat for Soap Making with Sheree Tompkins, June 19, 2013 for more on soap making.
See my earlier post: Soaps vs Detergents for more on their differences, etc..