By: kelbytv.com/photoshopkillertips/
In many cases, double-clicking on the slider name will reset the adjustment value back to zero.
http://kelbytv.com/photoshopkillertips/2010/05/19/quickly-resetting-adjustment-layer-sliders/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+PhotoshopKillerTips+%28Photoshop+Killer+Tips+%28Video%29%29