Re-dye your hair with a dye that has "ash" in the name. It will get rid of some (hopefully all) of the red tones.

use sher blonde in the darkest tone they have

You proly shouldnt recolor your hair- just find an ash toner.

sheer blonde does NOT tone down warm highlights. trust me, i use it everyday on my highlights (why waste the bottle when i already bought it?) and it has yet to tone down the coppery tones. don't necessarily dye it an ash tone.. believe it or not, your hair COULD end up grayish colored. not pretty. try a light natural blonde, and if it's still too brassy, then try an ash shade. but save ash as a last resort.

Use a toner like Born Blonde. It will tone down the brassiest hair. Pick Winsome Wheat. That gives you a nice natural blonde. You can buy it at a beauty supply store like Sally. It won't do anything to your other hair.

use silver shampoo i swear buy it!!

Oh My Gosh -- I had same question. Wrote to L'Oreal and asked them about returning product to the market and they told me that they never will do that. They suggested their new "toner" but I told them I used it twice and it didn't do a thing to help the brassiness. BUT -- Get this!!! I tried the new haircolor by Natural Instincts (Brass Free Blond -- medium blond) and IT WORKED LIKE MAGIC. Even my husband, who gets this horrified look on his face when I attempt to do my color myself at home (yes, I have a husband who WANTS me to spend almost $300/month at a fancy uptown Dallas salon!), told me that my color looks as good as or better than when I "get it done." And that's a HUGE compliment. This color (which I put on my roots for five minutes, and on my ends for only five minutes as the directions indicate) took all of the bleached brassiness out of my over-highlighted hair and it looks natural and blonde, and with tons of highlights. It didn't darken my highlights -- it only toned them to a natural "baby blonde" color and it warmed my natural dark ash blond hair to a nice neutral (non-ashey) blonde color. My few grew highlights are perfect blonde highlights and I'm so excited to find this "do it myself" solution that looks so good on a person like me -- on whom EVERYTHING I use at home turns brassy. So, wanted to share with you girls. Can't guarantee that it'll turn out that good for you, but I'm so excited about MY results that I just had to share! Good luck!!!