Soaking a ball in hot water and some kind of degreasing soap (like Dawn) is a common way to help remove any lane oil buildup.  Let the ball soak in a hot water and Dawn mixture for about 10 minutes, then remove it and wipe the oil off, repeat as needed.  Another variation on this is to put the ball in a dishwasher (turn the Heater Dry off).  

If you let the oil build up inside the ball, the ball's reaction can start to taper off or even die.  Wiping the ball off between every shot helps but there will still be some oil absorbtion, hence the practise of soaking the oil out.

Yep, the hot water and Dawn dishwashing detergent method works out pretty good for getting lane oil out of reactive resin balls.  Given enough lineage, a reactive resin or particle ball will eventually load up with lane oil and the reaction will die on you.  Periodic deoiling with the hot water method will help extend the useable life of a high performance ball.   Unfortunately, particle balls don't seem to respond nearly as well to this method of deoiling.  The safest way that I'm aware of to protect your high dollar ball investment is to pretreat the ball with Doc's Elixer, and retreat the ball every 25 games or so....this will help keep the oil from penetrating into the ball to begin with.