Hi i was wondering if anybody knows if theres a liquid or something i have a black board and in the top it lost color with the sun plus i was sandpapering the top to take scratches off, so anny polish to get color back???? Thanks!!!

i'm afraid it's gone.
you've sanded it off.

add any color of your choice.
paint,
gel-coat,
stickers (they all work)

...then sand some more
...then paint some more,
sand, paint .... ,
you'll get the hang of it

-bill