How to safely remove moss from shingled roof?

This week I noticed that my 12 year old roof has bright green moss on the shingles. This roof faces north/east and we have had two very wet summers in SW Michigan. I called our building contractor and he recommended bleach but I am not going in that direction.
I'm looking for a non-toxic solution that will not harm the shingles, cement porch, siding or landscaping. We are an organic homestead here that eats our food and drinks our water and use no bleach.
I've researched and find a number of non-toxic roof washing materials for moss (Like Roof Wash) so I think I am set there. But how to SAFELY remove the existing moss? I read about pressure washers (which we do not have though could rent) but I also read about not using a pressure washer when you are not used to using one due to potential damage.
My son who lives in wet Portland Oregon, land of the rain, said he was successful in getting up on his roof and scraping off the moss with a paint scraper. My IT type husband (not the skilled contractor type) wants to use a stiff, metal scrub but I am worried about him damaging the shingles...
Any other ideas/suggestions?
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