I recently came across this interesting ‘Did you know?’ fact that 71,001 tennis balls will be taken out of 23,667 cans in a single edition of US Open while Wimbledon uses a total of 54,250 tennis balls over the period of the tournament. 
The ball boys and girls are definitely kept busy during the tournament. 
What happens to these used tennis balls after the tournament is over? Resell, donate or … ? 
The balls are sold at the All England Tennis Club and funds raised are donated to charities such as the Balls for Schools scheme which helps support the tennis stars of the future.
At the Australian Open too the used balls are sold on site and fund goes to AO Community Grants programs supporting communities.
At Wimbledon, the balls are sold at the Used Balls Kiosk next to Court 14 the day after the match at a cost of £3 for a tin of three balls and £5 for a tin of six.
In 2001, 350 balls were donated to the Wildlife Trust who used them to help protect endangered harvest mice and create homes for them. Donated balls were attached to poles above ground and had holes bored into them that allowed the mice to safely build nests away from predators. Apparently, these mice loved their new homes. 
In France, L’Opération Balle Jaune took up an initiative in 2008 to recycle the 17 million tennis balls used every year in France including balls from French Open. L’Opération collects balls and turns them into coatings for sports hall floors. Collected balls are sent to a milling company where they are ground down and rubber is separated from the outer fabric by a ‘blowing process’. Using this process, 40,000 balls can be converted into 100 square metres of floor covering, and more than 30 completed sports floors have been produced using recycled tennis balls.
Through the L’Opération Balle Jaune project, France is now recycling around 10 per cent of its used tennis balls every year.
A similar project is run by Project Green Ball, a US-based voluntary product stewardship programme.
Tennis balls can also be re-pressurised to give them back their bounce extending their useful lives and reducing the need for new balls. This will reduce the amount of waste generated if not properly recycled.
Some creative ways of utilising the used tennis balls.
To stop the chairs from damaging delicate floors or to reduce noise, cut out small holes and slip the tennis balls over the legs of chairs. The same can be done with the legs of walkers to make them easier to slide over smooth surfaces.
… Interesting 
These tennis balls are used for different purposes.
Some people use these balls as token of love and keep them in their personal collection.
Some make decorative things from them.
People also use them for their pets.
