Cannabis Scratch and Sniff Cards

Dutch officials in Rotterdam and The Hague are hoping upwards of 30,000 people will commit their olfactory glands to the pursuit of illegal marijuana grow operations in Holland. The crime-busting plan involves sending out scratch & sniff cards impregnated with marijuana scent to 30,000 homes, hoping to educate people on how pot plants smell, so they can call police when they sniff-out an illegal grow-op.
The 8 by 4 inch (20 by 10cm) card calls on citizens to “Assist in combating cannabis plantations!”, with helpful sleuth hints such as looking for places where the curtains are always drawn, where there are buzzing noises, or illegal electrical hook-ups and, of course, the sweet, hay or sage-like aroma of healthy cannabis plants.
The Dutch government decriminalized the use and possession 5grams (0.18 ounces) of cannabis back in 1976, and people can generally grow up to five plants for their personal use without facing prosecution. However, black-market and criminal activities are valued at around €2 billion euros (US$2.7 billion) annually and may number up to 40,000 grow-ops.
Each year around 6000 illegal grow-ops are found, with around 300 in Rotterdam, according to Richard Anderiesse, who is part of the city’s cannabis task force. Concern about the grow–ops, apart from being illegal, include the risk of fire and water loss due to illegal tapping into the supplies.