Later, a flexible magnet was developed, composed of a high-coercivity ferrimagnetic or ferromagnetic compound (usually barium ferrite) mixed with a plastic binder,[4] extruded as a sheet.
Refrigerator magnets can be made from rubber, PVC, polyresin, metal, porcelain, epoxy, or a mixture of some of these materials.
At one time, the largest verified collection of refrigerator magnets belonged to Louise J. Greenfarb from Henderson, Nevada (suburb of Las Vegas, United States).
[11] Over 7,000 magnets from Greenfarb's collection were exhibited at the Guinness Museum in Las Vegas, which has since closed.
According to her son, Bryan Greenfarb, as of November 2015 Louise still collects and has around 45,000 plus non-duplicate refrigerator magnets but the Guinness verification process, which can take over 6 plus months, is just too taxing to keep validating the exact number.
In January 1999, Tony Lloyd, a teacher in Cardiff, Wales, was interviewed by the Channel 4 Television programme Collector's Lot when it was ascertained that he had the largest collection of refrigerator magnets in Europe at that time, over 2000.
In February 2018, whilst on holiday in Sri Lanka, his 104th country, Tony's collection surpassed 5,000 magnets.