Denicool. Put some crystals into the bottom of the pipe bowl, then fill the bowl with tobacco as usual. After enjoying the smoke empty the pipe together with the crystals. Denicool will have changed its color to dark brown because it is saturated with condensate. This proves its high efficiency as an absorbant. Denicool filter crystals ensure a cool, mild and dry smoke. They reduce tar and nicotine and absorb additional humidity while keeping the flavor of the tobacco.
Absolutely fantastic piece of invention, I use it for my 3mm pipes which can be difficult with paper filters. You fill these at the bottom of your bowl and it keeps the dirty stuff out! My only complaint is I hoped these can be made at a higher quality, for instance more controlled grain size; but they are consumables and are at a reasonable price.