I hear ya. Honestly, there have been so many EK quality issues and garbage implementations, I've given up trying to keep track. After years and years of sticking with them for everything wcing, I finally cut them off. When their pricing reached...
ive seen some report that theirs were clean after one good flush but for the most part they are pretty dirty and require a couple. Alphacool is about the same. IIRC Watercool/Heatkiller cleans theirs.
Some good reading.
https://www.overclock.net/threads/official-ek-statement-nickel-plating-issues.1035356/
http://www.xtremesystems.org/forums/showthread.php?271881-Official-EK-statement-Nickel-Plating-Issues