How to "dispose" a sprite?

[rigbycwts]

I was working on improving this tutorial to incorporate an image of a Gym Leader's badge at the start of a battle, similar to the Gen 6 games. At first it worked, like this:

Spoiler:

However, when the Pokemon are sent out, the badge image is still left on the screen instead of moving out with the sprite, like this:

Spoiler:

What I did is:
First, I added a new function to PSystem_Utilities:

def pbTrainerBadgeFile(type)
  return nil if !type
  bitmapFileName=sprintf("Graphics/Characters/badge%s",getConstantName(PBTrainers,type)) rescue nil
  if !pbResolveBitmap(bitmapFileName)
    bitmapFileName=sprintf("Graphics/Characters/badge%03d",type)
  end
  return bitmapFileName
end

Then I modified setTrainerBitmap to utilise the badge image:

def setTrainerBitmap(file,hasbadge=false,badgefile=nil)
    unless badgefile.nil?
      @bitmap=AnimatedBitmapWrapper.new(badgefile,TRAINERSPRITESCALE)
      @[email protected]
      @badge.ox=(@bitmap.width/2) - 100
    end
    @bitmap=AnimatedBitmapWrapper.new(file,TRAINERSPRITESCALE)
    @[email protected]
    @[email protected]
    #@sprite.ox=(@bitmap.width/2) + 150
    if hasbadge
      @sprite.ox=(@bitmap.width/2) + 60
    else
      @sprite.ox=(@bitmap.width/2) + 150
    end
    if @doublebattle
      if @index==-2
        @sprite.ox-=150
      elsif @index==-1
        @sprite.ox+=150
      end
    end
    @[email protected]/4
    
    self.formatShadow
    @shadow.skew(74)
  end

In the initialize function under the class DynamicTrainerSprite, I added the following line:

@badge=Sprite.new(@viewport)

Inside EliteBattle_Scene, I replaced:

@sprites["trainer"].setTrainerBitmap(trainerfile)

with this:

if @battle.opponent.trainertype > 58 && @battle.opponent.trainertype < 67
    @sprites["trainer"].setTrainerBitmap(trainerfile,true,pbTrainerBadgeFile(@battle.opponent.trainertype))
else
    @sprites["trainer"].setTrainerBitmap(trainerfile)
end

And that's it. So, how do I "dispose" of the badge image when the Pokemon are sent out?