not working - Box2D - cocos2d-iphone

Question

I am using tilemap in my box2D game in which I have created powers. When the player hits the power, a score label is displayed on the screen. Along with this I want to remove that power from the tilemap when player hits it. I have displayed label but I am unable to remove the power. Here is some code :
In ContactListener I am calling the method which removes the power from tilemap :
void ContactListener::BeginContact(b2Contact *contact) {
else if(actorA.tag==obj.gamePower.tag) //obj is a DataClass object.
{
[GameScene addPointLabel]; // For displaying score label
[GameScene removePower:actorA];
}
+(void)removePower:(id)sender
{
GameScene *obj=[[GameScene alloc]init];
CCSprite *sprite = (CCSprite *)sender;
[obj removePowerFromScene:sprite];
[obj release];
}
-(void)removePowerFromScene:(id)sender
{
CCSprite *sprite = (CCSprite *)sender;
[self removeChild:sprite cleanup:YES];
}
I have created an object layer on tilemap to display power. But somehow, I am unable to remove it. Can someone help me?

Answer 1

If power is a CCNode why don't you remove it with [power removeFromParentAndCleanup:YES] ?
The (removePower:) does remove nothing because it creates a new scene and remove the sprite from that scene where the sprite does not belong to.
Another notice, be careful with contact listener. Removing o node in BeginContact is potential of crash. Let imagine the case that powerA contacts with both actor1 and actor2. The first call to BeginContact with powerA and actor1 removes powerA, so subsequent call to BeginContact with powerA envolved will crash !