Funnily enough I wondered exactly the same thing last week. I took twice as much carbon as I\'d use in a z-filter and added it to a demijohn of 35%. I was using a few jars of heads which were quite smelly just to give it a really good test. Shook it a few times a day. After a week it smelled pretty much the same.
I filtered the carbon out using coffee filter papers.
I then took the 35% and ran it through the z-filter about 5 times. By the end of that the 35% smelled significantly cleaner than leaving it with the carbon.
I\'m still going to run it through the T500 when I get a couple more jars of heads/tails to really clean it up
