Clear bmp/sprites of the memory

[Godah]

Hi,

how to clear bmp/sprites of the memory?

I use this function to generate sprites of the lib:

addSprite(j * tilesDim, i * tilesDim, "spr_" + root["tile_" + map][i][j], mcTile);

function addSprite(X: int, Y: int, c: String, mc: Object) {
    cls = getDefinitionByName(c) as Class;
    bmp = new cls(0, 0) as BitmapData;
    sprite = new Bitmap(bmp);

    mc.addChild(sprite);

    sprite.x = X;
    sprite.y = Y;
    sprite.name = c;
} 

I already tried this:

bmp.dispose()
bmp = null 

But it does not work, the memory continues to increase. Any idea?