AutoreleasePool NSString Automatic Reference Counting I have some doubt about how NSString is released in ARC Mode.

I would like to know if have something i can do to release a nsstring when i want in arc mode.

Take a look at this code:

__block NSString *strImage = nil;
    dispatch_sync(backGround, ^{
        // Convert NSData To NSString.
        strImage = [UIImagePNGRepresentation([UIImage imageWithData:reg.photoData]) base64Encoding];
    });

    // Prepare Request Operation.
    NSString * strPost = @"myUrl";

    strPost = [strPost stringByAppendingFormat:@"}&amp;image="];
    strPost = [strPost stringByAppendingFormat:@"%@",strImage];
    //NSLog(@"POST: %@",strPost);

    // setting up the URL to post to
    NSString *urlString = @"myURLAPI";

    // setting up the request object now
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    [request setURL:[NSURL URLWithString:urlString]];
    [request setHTTPMethod:@"POST"];

    /*
     add some header info now
     we always need a boundary when we post a file
     also we need to set the content type

     You might want to generate a random boundary.. this is just the same
     as my output from wireshark on a valid html post
     */
    NSString *contentType = [NSString stringWithFormat:@"application/x-www-form-urlencoded"];
    [request addValue:contentType forHTTPHeaderField: @"Content-Type"];

    /*
     now lets create the body of the post
     */
    NSMutableData *body = [NSMutableData data];

    [body appendData:[NSData dataWithData:[strPost dataUsingEncoding:NSUTF8StringEncoding]]];
    // setting the body of the post to the reqeust
    [request setHTTPBody:body];

    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc]initWithRequest:request];

    //MY DOUBT ABOUT RELEASE THIS STR
    @autoreleasepool {
        strImage = nil;
    }


is it correct or have a best way to do it? Thank you
Also @autoreleasepool does not look are the objects create outside of it scope, just the object used within. Also if using are there is not need for the @autoreleasepool at all, since the scope variables will be released and nilled at the end of the scope.