<P> Prior to the 1950s, most curling brooms were made of corn strands and were similar to household brooms of the day . In 1958, Fern Marchessault of Montreal inverted the corn straw in the centre of the broom . This style of corn broom was referred to as the Blackjack . </P> <P> Artificial brooms made from man - made fabrics rather than corn, such as the Rink Rat, also became common later during this time period . Prior to the late sixties, Scottish curling brushes were used primarily by some of the Scots, as well as by recreational and elderly curlers, as a substitute for corn brooms, since the technique was easier to learn . In the late sixties, competitive curlers from Calgary, Alberta, such as John Mayer, Bruce Stewart, and, later, the world junior championship teams skipped by Paul Gowsell, proved that the curling brush could be just as (or more) effective without all the blisters common to corn broom use . During that time period, there was much debate in competitive curling circles as to which sweeping device was more effective: brush or broom . Eventually, the brush won out with the majority of curlers making the switch to the less costly and more efficient brush . Today, brushes have replaced traditional corn brooms at every level of curling; it is rare now to see a curler using a corn broom on a regular basis . </P> <P> Curling brushes may have fabric, hog hair, or horsehair heads . Modern curling brush handles are usually hollow tubes made of fibreglass or carbon fibre instead of a solid length of wooden dowel . These hollow tube handles are lighter and stronger than wooden handles, allowing faster sweeping and also enabling more downward force to be applied to the broom head with reduced shaft flex . New, "directional fabric" brooms, which players are worried will alter the fundamentals of the sport by reducing the level of skill required, have been accused of giving players an unfair advantage . The new brooms were temporarily banned by the World Curling Federation and Curling Canada for the 2015--2016 season . The new brooms give sweepers unprecedented control over the direction the stone goes . </P> <Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (August 2014) (Learn how and when to remove this template message) </Td> </Tr> </Table>

What is the bottom of a curling broom made of
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