I see that a lot of people are drilling out their old handles and then buying knotts and setting them way deeper than the originals. While I understand that they are doing this to get a stiff brush the problem that I foresee is that a larger portion of the lower bristles are set way below the top surface of the handle therefore I don't see how that portion of the knott can ever dry completely. This can lead to mold and fungus, these type of brushes will need to be sterilized very often. What are all of your thoughts?