How to remove black marks off after sanding?

Maybe a cabinet scraper.

-- You know, this site doesn't require woodworking skills, but you should know how to write.

Pics?

as on the other forum, the basic questions were not answered.
the marks are from the lumber mill – tool marks. (not the sander or sandpaper).
the black marks are probably aged wood (or mold) from being in outside storage.
the questions asked (and never answered) were:
what kind of wood
what kind of sander
what sandpaper
what are your realistic expectations for the project.
the sanding process is not finished – it still has quite a way to go.
(some people actually like the “rustic” look of reclaimed lumber).
and photos of the entire table could provide the most accurate responses.

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-- I am a painter: that's what I do, I like to paint things. --