Hi Darlene thank you for your difficult question ;-) Unfortunately, there is no refinishing technique that I am aware of that can polish out or refinish peeling or chipped pearls.
GIA have a cool color grading chart but it's not electronic, the problem seems to be that if one was attempting to grade pearls online, the color of the pearls, will vary depending on computer settings and monitors and things of this nature, and so basically, the color of the pearl will not be conclusive.
A pearl's color is described as a combination of the bodycolor and the overtone. Bodycolors are separated into two categories; cool hues and warm hues. Cool hues range from reddish purple to yellowish green while warm hues range from purplish red to greenish yellow. Overtone is the overlying color that appears to float over the surface of the pearl.
You can also read more information about pearl color and grading pearls at the Pearl Guide.
