Particulate reduction within the HDD is now a major focus driven by the dramatic increases in HDD storage capacities enabled by TMR, CPP, DSA and the new PMR media. The new PMR media is much more sensitive and therefore, prone to damage from these minute hard particles than the traditional longitudinal media. The Authors will describe the various methods utilized by the HDD industry to quantify cleanliness. Particle measurement metrology robustness and results will be discussed. Conclusions on particle contamination sources will be summarized from results obtained in multiple LPC ultrasonic extractions, process mapping, and component base material studies thereby, providing guidance to control final product cleanliness. Since dissimilar component materials behave differently under various ultrasonic washing power settings; products can actually erode, releasing particulate from the raw material instead of cleaning. Scientific methods of optimizing the final cleaning parameters to complement the base component material selection will be discussed in detail.