I love watching Hair101withApril and I have learned so much from her, when it comes to hair.
Recently she did a video on how to tone and care for hair extensions which I believe will help you if you have bleached blonde hair extensions and you want that ash blonde hair or platinum looking blonde hair.
And the best part is she didn't even use any color to do that. We are working on adding a blonde hair extensions that are more ashy, platinum, silver looking so that you don't have to worry about this step.
April had our light blonde shade that can be found here.
Also check out How to Care for Hair Extensions