What's the best way to prepare cypress and western cedar exterior siding for retreating?

Question:I've been told spraying with straight bleach and a quick water rinse to take out the "blackness". Would pressure washing to the job? Planning on using Sikkens Cetol to retreat.

Answers:
Nice stuff.
Bleach solution will work , but is not best choice.
It will mess up a power washer if that's what you had in mind.
Got to be cheaper , but it will give spotty results.
See if Sikkens makes a cleaner that works w/ their wood treatment.
Best to apply preservative soon as instructions allow.
Good luck