So after reading some articles about herbs and infusions and such where they suggest crushing the fresh herbs with a wooden spoon or pestle, I came up with this idea.
1 jar and lid
1 sprig of fresh sage (I used white)
1 sprig of green cedar
Put all the items in the jar and nail some holes into the jar lid. Close up tight and shake gently (dont brake your jar!)
The rock breaks the herbs and lets their perfume aroma swell through the holes.
Shake every time you want to freshen the air!