I wash my hair every day with a "blue" shampoo. I use whatever I can find. It's difficult to find these shampoos where I live. Sometimes I have to go to a beauty supply store.
RIght now I am using Jhirmack Distinctions Silver Plus and Pantene Silver Expressions and have several bottles of each in my cabinet. I buy it when I can find it,
Because my hair is super oily and I have to wash it everyday, I go through a lot of shampoo,
My hair is silver with a little black mixed... salt and pepper with very light Silver at my temples. I have had no trouble with my hair soaking up the blue color and looking unnatural.