will violet 'poo remove brassy from brown hair?

I used Clairol Nice'n Easy  #114 Natrural Light Ash Brown to match my hair and cover gray.  Even though it was ash based it came out VERY brassy, esp at the roots.  I called the Clairol hotline and they said do a soap cap with equal parts #114 color, the developer, and shampoo and apply to my roots, pulling down into the hair abot 2 inches to avoid a line of demarcation.  I checked my hair in the sun and noticed the length was also very brassy so I called back and they said put on all my hair length (mine is long, to the bottom of my bra strap) and check every 5 minutes,  When I did a test piece the bottom one inch it came out black after 5 mintes.  I did a test piece at the root for 20 min and there was no color change - brassy still there.  When I asked the woman at the Clairol hotline if I could use a violet based shampoo to be rid of the brassyness she said it would not work on brown hair, only blonde or gray.  I thought I had read it worked on brassy brunettes too?  Is she correct in saying it doesn't work for brown hair?  If it WILL work on brown hair what is a good brand?  I live near a Sally's Beauty Supply.  Please advise!  Thanks!

Why don't u read up on this coloring Shampoo or Cond?It's called ArcTec color Shampoo.it's a depositing color for all hair colors.It deposits color into the hair cuticle fiber.It adds color as u use it.I use the cond.everytime I wash my hair.I wash it everyone other day.It's very safe.Plus, it makes my blonde highlights so bright & shiny.They also have really pretty colors for brunettes to.If u don't know what color to get.Ask a hair dresser.I don't know of any toners that will tone down brassy color on brown hair. Just look up ArcTec color online & find the color u like. Good luck!