In primary school, the common practice for scraped knees was to clean the wound using hydrogen peroxide. Many of us might still do this, but this video from SciShow makes a darn good case for why we should just skip it altogether. We've written about this before, but SciShow delves a bit deeper into the interesting science behind how rubbing alcohol and hydrogen peroxide work and why the stinging sensation we all love-hate can actually be a bad thing. Clearly, the stinging means something is happening. We put up with it, though, because for the few seconds we may be suffering the bacteria must be getting it fifty times worse.
While that's true, it turns out the antiseptic is also killing our own healthy cells, which could slow the healing process. So, rather than using an antiseptic, SciShow suggests that you just stick to cold water and perhaps some soap to clean your wounds.