SomeObject.h

// I don't usually touch the AppDelegate anywhere else in the program
// so I'm not sure if this solves what you're trying to do or not.
// But, this should show the difference of how to declare public vs.
// private properties.

@interface SomeClass : NSObject {
    // If you use LLVM then you don't have to declare the private var!!
}

@property (nonatomic, retain) NSString *somePublicStringProperty;

@end

SomeObject.m

#include "SomeObject.h"

@interface SomeClass () // <- Empty parens means it's an anonymous category
                        // That makes it, in essence, private.

@property (nonatomic, retain) NSString *somePrivateStringProperty;

@end


@implementation SomeClass

@synthesize somePublicStringProperty, somePrivateStringProperty;

- (void)dealloc
{
    self.somePublicStringProperty = nil;
    self.somePrivateStringProperty = nil;
    [super dealloc];
}

@end