Clearing the Texture atlas?

Just wondering if I’m being an idiot, but I’m using some rather large images (using a retina iPad) and after I run my game once, stop and then restart. codea then is really slow in running the game.
I recon it’s the texture atlas rearranging it’s self, am I right? If so I will need texture atlas control later on in my game for level transitions as there will be a ton of textures.
Does that exist already? Sorry if it’s a dumb question.