Instructions
Consider whether you want to do multi- or single-ball contact juggling. For multi-ball juggling, a ball under three inches is best. For single-ball juggling, a three to four inch ball is ideal. Pick a ball that fits easily in your hand.
Choose a ball without any visible seams or "tell marks." A tell mark is any mark that breaks the color of the ball. The basic idea is to have a mono-color ball.
Weigh the ball in your hand. A contact juggling ball is heavy enough to give the manipulator a sense of control when rolling the ball. The ball should not bounce much when it falls to the floor. Contact jugglers call this a "dead drop," which makes it easier to retrieve the ball when it falls.
Check the ball for a smooth surface. Any ball you choose should roll smoothly against the same type of surface material. Silicone and acrylic balls are popular among seasoned contact jugglers.