This is something you should know for all shaving brushes. Soap will build up no matter how well you rinse after use. After awhile the performance will go down hill due to soap build up. Hairs will also start breaking off around the knot as well due to soap scum. I do this with my animal hair brushes once a year when I get the white rim around the base: How to Clean a Shaving Brush - https://www.badgerandblade.com/forum/wiki/How_to_Clean_a_Shaving_Brush
Yeah sure, I meant how they handle brushes from germophobe standpoint