When a tip starts getting towards the end of its natural lifespan and becomes slightly thinner and harder than the player normally prefers, it is possible to soften and thicken the tip back to its original consistency (say 10 to 15 playing hours ago) by wetting the whole surface area of the tip and leaving it to dry for couple of hours. This can be done on more than one occasion with the same tip, and is very useful if the player has a match in the near future and is loathe to change to a new tip.
Most players have at one time or another dented or nicked the shaft of their cue by accidentally dropping it or knocking it against something, in fact some players even hit their cue against the lightshade by virtue of their own eccentric cue action (hello Jock). A nick or small dent in the shaft of a cue can easily be removed with sandpaper, but provided the fibres of the wood are not torn or cut and the damage is just a dent, there is no need for this drastic action to repair the cue. Lay the cue down horizontally with the dent uppermost and place a drop of water on the dent, then leave it to dry. This may have to be done a couple of times, but its effect is so dramatic, that sometimes it is not possible to detect the original damage. It is also noticeable that the more recent the damage the more effectively the method works.