The following response comes from internationally acclaimed salon colorist, educator and product consultant, Beth Minardi. She is recognized as one of the world's leading experts in all phases of coloring.

Shiny Silver

The Challenge: Fellow colorist, Heidi, and her client nightmare: A former color client wanted to grow out her hair to its natural color. The front was 98-percent white, the back was 80-percent white, and the rest of the hair is a Level-6 ash shade. The client spends a lot of time in the sun and her white hair is yellowing. She tried using Matrix So Silver Shampoo, but it did not completely solve her problem. The client is going to a class reunion and wants the yellow out of her hair. Heidi pointed out that the client does not want to return to full color, so she is at a bit of a loss.

Beth's Solution: This problem is not uncommon. The client's hair might be yellowing due to mineral buildup. While a silver shampoo can sometimes help, the colorist might try removing mineral buildup first, and then using a "silverizing" product.
The best remover of minerals, chemicals or semi or demi color stain is a product called Get Pure. It is made by the L'Avant Garde Company based in Simi Valley, California (www.lavantgarde.com). If you do not have Get Pure, try using the Malibu 2000 product, Redken Pre-Art or a liquid product made by Clairol called Clairol Liquid Uncolor. In each case, follow package instructions. Then, wash the hair with a "silverizing" shampoo and conditioner. 

Eugene Perma Professionnel makes a semipermanent color called Blush. The silver-white shade makes white hair look shiny and silver. It's applied to shampooed, towel- dried hair for 15 - 20 minutes and is then rinsed out. Another great product is Pravana's semipermanent "silk" crème color in Platinum.