Abstract: Thermally assisted processes for removing internal defects in glass ceramic products, specifically electrical shorts formed in a substrate during product fabrication, are set forth. According to one aspect of the invention, a method for repairing shorts between metallic conductors located within in a glass ceramic product, such as an electronic substrate, comprises the steps of (a) pre-conditioning the glass to resist cracking from the generation of heat by any shorts melt down current subsequently applied to said conductors; and (b) subsequently applying a melt down current to said conductors to repair any short located therebetween. The aforestated method minimizes the potential for glass damage resulting from defect repair activity and optimizes defect repair yield.