Grey Group Poland recently roped in the country's largest retailers and the Polish National Fire Department to distribute a flier that looked like any other that arrives with the newspaper or in the mail. The difference was in how Poles were told to use it.
Instructions on the leaflet told the recipient to hold it up to a home intake vent. If it sticks, the house has good circulation. If it doesn't, the vent might be clogged and could pose a carbon monoxide threat.
Odourless and deadly carbon monoxide kills about 100 Poles each year. Twenty-eight million copies of the fliers distributed reached 40 million Poles.