I wrote the following code to make my toolbar transparent.
[mtoolbar setBackgroundColor:[UIColor clearColor]];
How do I make UIToolbar
This worked for me for iOS 6 and 7:
UIGraphicsBeginImageContextWithOptions(CGSizeMake(1, 1), NO, 0.0);
UIImage *blank = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[self.toolBar setBackgroundImage:blank forToolbarPosition:UIToolbarPositionAny barMetrics:UIBarMetricsDefault];