If one could put juice down the center of the tank to the coil, then if put in a pocket or the winds blowing etc Anything can build up in a tank, tip etc. Mold spores, pollens and pocket fuzz, IMO. I clean (at least once a week) the whole tank, in boiling water, several times. Pull the seals air dry and wipe down and clean the tip. Seen the juice and condensation under and in the drip tips.. I have. Its a easy place w perfect dark warm moist environment for growth yuck!