So I reached into my used filter bowl and grabbed the skankiest-looking filter I could find, popped it between my lips and gave it a draw. Surprisingly, there was almost no taste at all. The paper and the charcoal work well together to capture the tars and lock them in.Vauen's website suggests every use for "Maximum enjoyment". Of course they are selling them. Most online pipe shops suggest a maximum of two to three uses. Most the time they are clogged after 2. Vauen pipes are also designed to minimize flow around the filter. A lot of other pipes allow this. I prefer a little flow around for a free draw.
I typically trashed a filter when it got to this state but I think I could get even more use out of them. This calls for a little experiment...