Q: How do I measure the amount of contaminant on my boards?
A: The common methods are IC, ROSE and SIR
Q: Do I need to clean No Clean flux residue?
A: As discussed, it depends on the board design and mission of the board. If the cost of failure is high, cleaning is required.
Q: Is partially clean good enough?
A: You have seen the partially cleaned SIR charts moments ago. The data shows that partially cleaned is not sufficient. You must fully clean off all residue if you decide to clean.