How do I stop from having colors left over on the edges

I am making a game similar to space invaders so the player fires upward, when a shot leaves the layout it is destroyed. But for some reason it leaves a bit of color on the edge of the screen. In fact any sprite leaving the screen leaves color on the edge.

I have used debug mode to verify they are getting destroyed. Even an explosion close to the edge seams to bleed color that permanently stats on the edge of the screen.

Can you post a capx?

what most likely is happening is your background it not fully covering the screen to fix just make sure your backround images is bigger then then layout if thats not it we need to see a screenshot or capx to help