ref – http://stackoverflow.com/questions/12318398/how-can-we-explicitly-call-garbage-collector-in-arc-also-is-there-a-way-we-can

There is no garbage collection with ARC, so there is nothing to call. If you control the scope and ownership of your objects, ARC will look after the memory use for you.

Apart from assigning ‘nil’ to a reference or letting the reference go out of scope, the only other consideration is whether you have some extra reference to the object (such as putting it into a NSArray) that has it’s own need to retain the object.

Note: An object pointer (or reference) gets pushed onto the stack. When you go out of your scope, that references gets popped, thus essentially nil-ing it.

Or in other words, pointing the reference away from the object on the heap, and thus making a -1 on that object. When that object has NO strong references to it anymore, it’s dealloc will be called.