Digging out your favorite pool cue from the basement or the attic can bring you from joy to sorrow when you see the cue has become warped. Even the slightest warp in a pool cue will render it useless. Straightening a warped pool cue is relatively easy, but it may take a long time. Patience will bring the rewards.
Check to see if the pool cue is warped. Lay the stick down on a flat, level surface--a billiard table is perfect--and roll the stick across the table. If the tip goes up and down as the pool cue rolls, the stick is warped and will need to be straightened to play properly. Hold the pool cue by the butt and look directly down to the floor at an angle to see exactly where the bend is.
Find a damp place high enough to hang the pool cue for a long time. The cue will need to hang loose from the ceiling and remain damp for quite a while.
Put a string through the center of the tip clamp, and place the tip clamp on the cue.
Lightly sand the varnish from the shaft of the pool cue. Don't worry about the tip area; the warp is not in that end.
Tie the string over the pipe or beam you have chosen. Spray the cue liberally with water, and keep damp and warm (80-plus degrees). Fill a couple of old tube socks with sand for weight and tie them to the butt of the hanging pool cue. Make sure the pool cue is hanging absolutely straight with a level.
Leave the cue hanging unimpeded for several days, checking only on humidity and heat levels. After a few weeks, check straightness with the level, without taking the pool cue down. Continue to monitor the warped pool cue until it has straightened to your satisfaction.