Our exterior soffits and carport ceiling/roof decking (pictured) are pine T&G. At one point they may have been treated with preservative but hard to tell. Were never pained/stained. Original to home, circa 1980.

What would be some courses of action to restore and preserve what remains? There is the typical greying, nail stains, mildew, knot bleeds, etc. So, I am not looking for miracles, just to make it as clean, consistent as possible with an eye toward some kind of renewal and doing what I can to avoid further decay. Above the T&G is just roof decking and asphalt shingles which I will be replacing as well so further leaking issues will be resolved.

I have re-sided the interior and exterior of the carport, which will be painted hardie board and batten, but would love to give this ceiling a cleaner look as it is visible from inside the house.

I will be pressure washing in advance of painting and figured I would try a cleaner/mildew remover on the ceiling and then perhaps some kind of exterior stain or seal. Recommendations appreciated!