One particular study that is worth mentioning examined use of HTPs in humans in Japan, and assessed users after 90 days
Activated carbon filters are designed to catch some of the resin and tar thats produced when smoking, using a process called adsorption
28 While the differences in radical delivery between the CF and AF cigarettes tested may be due to the presence of charcoal, it is also possible that differences in other cigarette design factors such as tobacco blend or ventilation may be involved
In our modern time, this is now considered a standard for all rolling papers for an easy roll and to prevent it from ever affecting the taste of the flower
While there is still a lot of research to be done on the dangers of e-cigarettes, it is clear that there is much to be concerned about
If that doesn't work, try a professional steam clean