Inactivating Hep B

The risk of transmission in this way is probably really low. There’s more information here:


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Hello everyone!
I have a silly question (just double checking to ease my mind). I cut myself with a friend’s swiss army knife. My first thought was to buy him a new one but this one was gift.

I was wondering how much time should I immerse it in undiluted bleach to be 100% sure that there is no danger if he cut himself in the future. Is one hour long enough? Should I use undiluted bleach or water helps in activating the sterilizing abilties of bleach? Should I follow up with something else?

I know I’ve asked this question before but given that this is a knife and the risk of cuting himself with it in the future is reasonably high, I am just checking to make sure that I don’t mess things up.

Hi @Drew_rous,

As mentioned above, warm soapy water is sufficient to inactivate the virus. Undiluted bleach is much, much more likely to damage the blade and cause pitting, which means more gunk can get stuck in there and limits the use of the tool.

Hope this helps,

Hello @ThomasTu,
I understand that but I would be much more comfortable using bleach. I know I am overacting but immersing it in bleach makes me feel sure that there is no chance I didn’t wash it well enough.

Sorry for spamming you but in that case what would be the appropriate time that needs to stay in the bleach? Is one hour enough?


Diluted household bleach disinfects within 10–60 minutes contact time

I understand your concerns, but using such a strong agent could damage the blade and make it more dangerous for the user (not only make it less sharp, but the pitting could make it more likely to be contaminated by other things). We have provided suggestions above of what would inactivate hep B coming from a scientific lab where we measure these things with very high sensitivity.