You only need a clothes-peg and a 4x1 cm piece of corkwood (easy to make from a cork too) or a few cotton balls. Glue the corkwood or cotton ball on the top part of the peg. Put 3 drops of Grapefruit (Citrus x paradisi), or Eucalyptus radiata in times of colds and flu or pick your own choice of oils! Clip the instrument onto one of the car ventilation grids on the dashboard. Voila!
