I have a line of moss which has grown between the first shingle at the edge of the roof and the plywood below. I am hesitant to scrape the stuff as I may damage the shingles. I was reading through your website and saw the suggestion about using bleach water to kill the moss and installing a zinc strip near the peak of the roof. As I do not have any growth on the roof itself, would it be advisable to install this zinc strip at the EDGE of the roof? In my mind this will help ensure that all water gets to the gutters and doesn't leak under the last shingle. I am concerned about other issues I may not know of.