Washing your glasses with soap can help prevent fogging when wearing a mask

30th Jul 2020

Claim

Washing glasses with soap will prevent lenses from fogging whilst wearing a mask.

Conclusion

This is true. The soap disrupts the surface tension which causes the condensation or “fog”.

We’ve seen social media posts and articles about how soap can prevent people’s glasses from fogging up when wearing masks. The posts say that rubbing soap or washing up liquid on lenses forms a protective barrier that prevents the condensation or “fog” happening.

This is true. The advice generally states that fogging occurs because the mask pushes warm air expelled from the mouth and nose onto the cooler surface of the glasses. By washing glasses in products like soap or washing up liquid, you disrupt the surface tension and prevent the lenses fogging up. The advice comes from medical professionals who have had to wear masks and glasses together prior to the beginning of the coronavirus pandemic.