SN74HC273: Clarification on how to detect corroded pins

Part Number:SN74HC273

Hi E2E,

Good Day! 

In relation to this topic, https://e2e.ti.com/support/logic/f/151/t/718449 

1. How can we detect if it is a corrosion or not?
2. Why can’t them be soldered sufficiently in the wave soldering process?
3. Is there a special flux necessary?

Thank you in advance for your help. 


Regards,
Ron