The propolis (entrance to a city in ancient Greek) plays a protective role in the hive. Collected by bees from specific tree buds (chestnut, birch, poplar), it is a disinfectant and a natural antibiotic. Omnipresent in the hive, the propolis is used as a natural shield by the bees to clean up the hive by sanitizing it and preventing the spread of microbes and diseases, but also to fill its cracks and ensure its tightness. To free the frames stuck with propolis, the beekeeper uses an iron frame lifter equipped on its rear part with a plane that scrapes off the excess of wax and propolis.