We have cedar siding on our 2 year old house. After the siding was installed, we sprayed it with TWP stain. We used the Honeytone color which we were warned had the least amount of pigment and uv protection. After two years we are noticing some light greying on the bottom boards on the two sides that receive the most sun. We want to clean that off and have been told by TWP to use their cedar cleaner which they said is similar to a deck wash(I presume that it has some acid and clorine in it). TWP suggested we use a pump sprayer to apply the cleaner and to saturate the boards we want to clean and, after 10 minutes, lightly pressure wash the boards to remove the cleaner. They say that the boards will be restored and, after waiting a couple of days, we can reapply the TWP. They also told us that, if the other boards that haven't greyed will absorb water(using a hose) we can go ahead and apply more TWP to those areas.
I would appreciate any comments about this process from people who have dealt with this kind of siding and stain and the kind of situation I have experienced. I am especially interested in experience with the greying issue and how to remove it. If pressure washing is involved, I need to buy a pressure washer and would appreciate recommendations and suggestions about the pressure to use.
Thanks for any help.