A system and associated method are used for warming an endoscope, laparoscope, or other such instrument to minimize fogging. A flexible pad has a length, a width and a periphery for wrapping around the instrument. An activation disc and a mixture of water and sodium acetate are used to generate heat through an exothermic reaction initiated through manual manipulation of the disc. The disc may be exposed in a flexible tab in fluid communication with the pad. A housing includes an end bore to receive the instrument such that the instrument is surrounded by the folded or rolled pad within the housing. The housing may further include a slit or narrow opening enabling the tab and activation disc to extend therethrough and outside the housing for activation.