Bleach And “Washable” Paint

As you all know by now motherhood comes with a lot of laundry. Who knew such small people could create massive piles of dirty clothes? My least favorite is what I call The Stain Wash: clothes that had extraordinary encounters with ink, blood, and who knows what else.

This week I found myself battling the stain of all stains, washable brown paint. Yes, I said washable. My daughter came home from preschool with it on her dress. I thought “it will come right out, it’s washable!” Wrong.

The paint held on through the first wash, and resisted Oxiclean’s oxygen action. I then tried my grandmother’s old stand-by, Fels Naptha bar soap. This gets out just about everything. No luck. Then I tried Clorox Bleach Pen (it is a white dress with black dots). The stain was still there. 

Eliminating this stain had become my new mission. I decided to put full-strength straight bleach on the stain, applying it with a small paintbrush hoping to avoid discoloring the black dots. The results are in the photo below.

Even bleach failed to conquer the washable brown paint stain. I had always believed bleach to be the be-all-and-end-all of stain removal. This got me thinking...what exactly is bleach, how does it work, and why didn’t it work this time? I found the following explanation helpful:

Ordinary table salt (sodium chloride, NaCl) is half chlorine, and a simple electrochemical reaction with salt water produces chlorine gas easily. That same reaction produces sodium hydroxide (NaOH), and by mixing chlorine gas with sodium hydroxide you create sodium hypochlorite (NaOCl). When you buy a gallon of bleach at the grocery store, what you are buying is the chemical sodium hypochlorite mixed with water in a 5.25-percent solution. You're buying salt water that has been changed slightly by electricity.

Chlorine also makes a great stain remover, but not because of the chlorine itself. Natural stains (as well as dyes) produced by everything from mildew to grass come from chemical compounds called chromophores. Chromophores can absorb light at specific wavelengths and therefore cause colors. When chlorine reacts with water, it produces hydrochloric acid and atomic oxygen. The oxygen reacts easily with the chromophores to eliminate the portion of its structure that causes the color. (howstuffworks.com)

Aha! So a chemical reaction changes the molecular structure of the chromophores, inhibiting their ability to produce color. Now I understand how bleach works. But why didn’t it work on the dress? Dr. Laundry does not recommend using bleach on spandex, and my daughter’s dress was a cotton-spandex blend. Maybe that small percentage of spandex was enough to keep the bleach from being 100% effective.

So, the next time you turn to bleach to salvage that outfit you just bought, you will have a little more insight into how it is working...or isn’t.

As for the fate of the dress? I decided to live with the light stain that is left on the back, and I filled in the discolored black circles with a Sharpie. 

If you would like to share some science with your kids, click here for an experiment about separating colors.