I want to clear my cache in my application. Some times, my application get crashed due to some memory warning like, 

```
      Received memory warning. Level=1

      Received memory warning. Level=2

```

In my application, i have used asynchronous method and downloading image in cache and displayed in the view. so how can i clear the image cache. how do i solve this problem. 

Please help me out. 

Thanks!