As far as gutter whitening, I would like to see product comparisons. Gutter Grenade, Gutter zap, super clean..etc etc. Maybe in different temps too.
With clean outs, I would like to see how people are doing the job. I use the old fashioned bucket and rubber glove method. Then I run a hose down the downspouts. Works every time.
I've heard of people using vacuum systems on them. I would like to see the effectiveness of that.