Sand? Chlorine TriFluoride
Chlorine trifluoride and gases like it have been reported to ignite sand, asbestos, and other highly fire-retardant materials. In an industrial accident, a spill of 900 kg of chlorine trifluoride burned through 30 cm of concrete and 90 cm of gravel beneath.
The compound reacts violently with water-based suppressors, and oxidizes in the absence of atmospheric oxygen, rendering atmosphere-displacement suppressors such as CO2 and halon completely ineffective. It ignites glass on contact.
It is extremely reactive with most inorganic and organic materials, including glass and teflon, and will initiate the combustion of many otherwise non-flammable materials without any ignition source. These reactions are often violent, and in some cases explosive. Vessels made from steel, copper or nickel resist the attack of the material due to formation of a thin layer of insoluble metal fluoride, but molybdenum, tungsten and titanium form volatile fluorides and are consequently unsuitable.
Not sure how you modify HDD to use it. Sounds like it will do in SSDs too!
It's likely you are mad if you consider it as a rocket fuel
It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water