Heat sink compound, which is also called thermal grease, thermal paste thermal compound, CPU grease, heat paste, heat sink paste, and thermal interface material, is designed to efficiently transfer heat away from a heat generating component. For electrical applications, heat sink compound is used to thermally bond a component with a mechanical heat sink. The compound fills the gap between the CPU (central processing unit) or other heat generating components.
In addition, heatsink paste is used with thermocouple wells, thermistors, and calrods, or wherever efficient cooling is required. Although heatsink paste does not have the thermal conductivity of metals like copper and silver, the improvement over the air will increase thermal responsiveness.
Try adding VMP naphtha (a common paint thinner) to the compound at approximately 1 part VMP to 100 parts compound. Mix thoroughly to get it back to the consistency required. This is mostly by “eyeball” so you may need a little less or a little more, depending on how dry the material is.