Lay the ball flat on the floor and allow it to warm to room temperature. Smooth out the wrinkles and inspect the ball for any holes or defects. If you find any, avoid inflating the ball and return it to where it was purchased.
Locate the small, needle-like plug or stopper. Depending on the brand, this may already be installed in the air intake hole or taped to the side of the ball. If it's taped to the side, peel off the tape, set the stopper to the side and skip to Step 4.
Remove the installed plug or stopper with the provided fork-like plug removal tool. Slide it under the top of the stopper and move it up and down to lift the plug enough to grasp it with your fingers. If a tool was not included, push the edge of a coin under the lip of the stopper, and rock it up and down until the stopper lifts enough to grasp and pull it out.
Prepare your pump. If a foot pump came with your ball, assemble it according to the manufacturer's instructions. Provided hand-held pumps come assembled. You can also use a bicycle pump, or an electric air compressor with a special adapter or nozzle.
Insert the pump's nozzle or adapter into the air intake hole, and inflate the ball to about 80 percent of its maximum size. Remove the pump and quickly insert the plug.
Complete the inflation process after 24 hours -- allow the air to expand. Repeat Steps 3 through 5 to inflate the ball to its maximum recommended size. Check the size often by wrapping a measuring tape around the circumference of the ball. Remove the pump and push the stopper into the ball until it is flush with the ball's surface.
Follow the instructions in Step 3 of the Inflating Process section to remove the plug.
Skip to Step 3 if you have a weighted ball, otherwise, force the air out by pushing on it or by sitting on the ball and squeezing it between your legs. You can also lie on the ball and roll back and forth. An alternate method, providing you have a dual-action pump, is to insert the nozzle into the hole and pump out the air. Skip to Step 4.
Turn the ball so the plug faces the ceiling and keep it in this position so the sand stays at the bottom while the ball deflates. Avoid forcing the air out by squeezing, sitting on it or rolling while lying on top because you could lose the sand. Allow the ball to sit, undisturbed and deflate naturally. If you have a dual-action pump, insert it into the air intake hole and slowly pump out the air.
Flatten the ball once most of the air has been removed. Use your hands to smooth and push out the last bit of air. Put the plug into the air intake hole for safekeeping.