Even if they do kill pathogens in the nose, germs can still enter through the eyes and mouth, Dr. Tierno says.

WSJ: Keeping Cold and Flu Germs Out

Earlier this year, Jandira Barone, owner of denim company Tristar, made headlines when she suggested a water-free denim cleanse throwing jeans into the freezer to kill germs.

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Wrigley also agreed to remove labeling on the products that indicates they kill germs.

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Unlike chemotherapy, which uses chemicals to poison cancer cells, Rituxan's monoclonal antibody kills tumor cells much as the body's own antibodies kill invading germs.

FORBES: Follow Through

Scientists at the University of Glasgow have developed a prototype plasma device which creates ozone to kill germs in packaged food.

BBC: Plasma device developed to 'sterilise' food