Wash your balls. In the washing machine. With your sports clothes.
The idea
A shiny squash ball will skid on the floor, making the bounce unpredictable. Having non-slippery squash balls is important for consistent bounces. You can buy devices that "scrub" the ball, or you can rub them on carpets, but the simplest solution is to just add them to your sports wash.
What to do on court
Don't wait for a ball to become shiny, smooth and covered in wall paint, stencil ink or wall plaster. Add your squash balls to your washing every few plays. At 30 degrees, the wash will not damage the ball, just abrade the surface enough to make them more consistent. Try the device, carpet or even light sandpaper if you want, but honestly, the easiest method is the washing machine.
