You have a Vicks or similar vaporizer, keeps the air from getting too dry in the winter and you want to clean it. You know that steam cannot contain bacteria and is sterile already, but you may be overly concerned and want to clean it anyway. Ok, we got it. Cleaning also makes the unit work more efficiently.
Do the following in a kitchen or bathroom with a flat water-resistant surface and near a faucet. You will need vinegar and bleach. Make sure the unit is cool, wait 20-30 mins for the unit to cool, if it was just being used.
The above is a summary of a YouTube video.