Clorox Hand Sanitizer Testing

Clorox hand sanitizer is one of the few that I recommend because it has been tested and shown to kill the norovirus surrogate. It works well on relatively "clean" hands and does not leave a sticky film. If your hands are dirty, it would be best to wipe them off before using this hand sanitizer. This sanitizer is alcohol and can sting dry or cracked skin. 


Clorox® Bleach-Free Hand Sanitizer


For this experiment, we tested Clorox Bleach-Free Hand Sanitizer spray which is 71% ethanol. I like it because it claims to kill norovirus. After preschool, Katie Scarlett pressed her unclean left hand into the agar plate. (Her hands were not visibly dirty.) Then we sprayed both hands with lots of Clorox Bleach-Free Hand Sanitizer spray. I used 10 sprays on each hand, and her hands were soaked and dripping. She rubbed them together until they were dry. Then she pressed her right hand into a sterile agar plate. After incubating for 24 hours, only 1 colony of bacteria was visible on the plate with the sprayed hand. The Clorox Bleach-Free Hand Sanitizer spray did an excellent job of killing the bacteria on her hands.




I also tested Clorox Bleach-Free Hand Sanitizer spray on my father when he stopped by to visit. It worked great but there were a few tiny colonies left on one fingertip. This shows that it is very important to use plenty of spray and to get it everywhere.  Alcohol sprays work well on "clean hands" but don't work well on dirty or soiled hands as you can see in the next experiment. 



How well does Clorox sanitizer spray work when you use a NORMAL amount?


In the previous experiments, I sprayed 10 sprays of hand sanitizers on each hand. The hands were dripping wet and fully covered. But no one REALLY does that. People would put 2 sprays on one palm and then rub the hands together. So, I tested this. After school, my son Jon pressed one dirty hand into an agar plate. Then I sprayed only 2 sprays of Clorox Hand Sanitizer on his other hand. I rubbed it in with one of my hands. As you can see, it really didn't do anything. The bottom line is that you need to use A LOT of hand sanitizer to fully cover your hands if you want to actually kill most of the germs. 



Does Clorox hand sanitizer spray work when your hands are visibly dirty? 


After school, Jon came home with visibly dirty hands from playing on the playground. There was a light layer of dirt on his hands. He pressed his dirty left hand into the agar plate. Then we sprayed both hands with tons of Clorox Bleach-Free Hand Sanitizer Spray. I have never used this much spray. Jon rubbed and rubbed his hands until they were dry. His hands looked a little cleaner but were still dirty. He pressed his "clean" right hand into a sterile agar plate. 

After 20 hours of incubation, both plates grew approximately equal amounts of bacteria. So, Clorox Hand Sanitizer Spray (and most likely other alcohol sprays) don't work if your hands are soiled. 

Comparing Homemade Thieves/Witch Hazel Spray with Clorox Hand Sanitizer Spray


For this experiment, I made my own Thieves hand sanitizer. I used 15 drops of Young Living Thieves oil, 1 teaspoon Witch Hazel, and 5 teaspoons of distilled water. I put it in this amber glass spray bottle. Since it is a spray, I compared it to the Clorox Hand Sanitizer Spray  that I purchased from Amazon. (The Clorox Hand Sanitizer Spray is primarily ethanol and does not contain chlorine bleach.) For this experiment, I had the kids rub their thumbs all over the dirty control plate. Next, I sprayed 8 sprays of the homemade thieves spray all on their left fingers, and I rubbed it in with my clean gloved hand. I let it sit for 1 minute, and then the kids rubbed those fingers all over the agar plate. Finally, I sprayed 5 sprays of the Clorox hand sanitizer all over the right fingers. I only used 5 sprays because that seemed to make the fingers wet enough. I rubbed it in with my clean gloved hands and let it sit for 1 minute. Then I had the kids rub their right fingers all over another plate. I incubated the plates for 24 hours in my warm incubator to let bacteria grow.




As you can see, the homemade thieves spray killed some germs but I don't think it does enough to be actually used as a hand sanitizer. I wouldn't trust it. It is also important to note, that these hands all looked clean. They did not have actual dirt on them. My experiments show that most hand sanitizers (except Zylast and a few others) don't work well on hands covered in actual dirt.