removing roof moss while protecting the roof?

I have been using a chemical based Moss remover for my roof since 2006 and now most of the shingles have lost there aphsalt. What can I use that won't  destroy a roof?

Depending upon the shingles, 14 years is a reasonable lifespan.   You may want to consider a metal roof.

Only half the roof is this way the other side is fine where its not shaded. I plan on selling my house next year so paying for a new roof is out of the question. My metal sheds only lasted 18 years and are totally rusted now. I live in the Pacific Northwest with a roof that is not pitched correctly for a metal roof at all.

Well....

While it won't help an already damaged roof, , a broad copper ridgecap (that is raw copper with no sealants!) helps inhibit moss growth, Ditto for galvanized.....
For some reason many jurisdictions have outlawed these proven solutions and perhaps there will be unfortunate consequences in flower borders, a horticulturist might have answers.

I remember the 1st house I had we put on a new roof with a zinc strip across the top and no moss grew on the roof. I guess I will need to scrape it all off by hand when it's dry and warmer to do so.