blonde hair looks dirty :(

I'm a little frustrated, I've been doing my roots for a year now and for some reason lately my hair looks like its a dirty color, not white, not yellow but like a pale mix...or not uniform. I'm not sure what's going on. anyways here are some pics, like I said.. I only do the roots and I really don't want to dye/streak my hair. I've used purple shampoo when my hair feels brassy but havnt used it in a while. I tried a clarifying shampoo, made my hair feel great but still the color looks crappy. here's some pics... any advice would be appretiated!!

Silly Hal, more pictures won't help!  Are you bleaching your roots?  What are you doing to your roots?  Sometimes ash colors tend to look blah, just add a little warmth to the color you are using to spice up the tone of your hair a bit. 

It looks like an ash dye or toner was used and has stained the hair. It should fade. Like Rebekah said, add warmth to the hair to brighten it.

I like the colour with the purple shampoo, personally. It might just be my laptop but there seems to be a purple tinge to it in that photo. Hardly noticable, you'd have to be looking for it.

I don't think you should add more bleach on top of that, maybe just a high lift dye.