Here's our favorite blog post from the March 10 ezine. It includes more information on the dangers of using bleach:
For pots that may have been washed with a bleach based product repeatedly or simply soaked in bleach, we would suggest a simpler, more environmentally friendly approach.
You should soak the piece in a solution of white vinegar and water. The purpose of the vinegar is to neutralize the effects of the bleach and stop the disintegration of the piece. After soaking the piece in the vinegar solution, clean and soak in distilled water to remove the vinegar.
Should you need to lighten the crazing lines on a piece, never use bleach. Instead, use hydrogen peroxide, the kind sold at the beauty stores for bleaching hair. You can soak the piece in the peroxide, then wash well and soak in distilled water. (Use gloves.) Some pieces may need more soaking than others.
Gusten's Restoration Studio