The first thing you need to know about achieving silver hair is that it isn't easy, if you have brown hair and you want to get it to silver it's going to be a really long process you need to get it bleach blonde before you can get it silver. I'm in no way a hair dresser, this is just my own personal experience with getting my hair silver!
First off I bought 'chroma silk vivids' it's just a normal silver hair dye you can mix with white conditioner, i love it there's only one bad thing I can say about it and that's the price - I bought it off Ebay for £30, pricey for just a hair dye I know, but I have tried a lot of other silver hair dyes and toners and this seems to be the only one that works for me!
To keep my hair silver as long as possible I use 'fudge clean blonde' toner on my hair once a week! This stuff is so pigmented but amazing! It also took me a while to find a good toner, I swear by this one.
Lastly to take care of my hair as all the dying and bleaching can cause damage I apply castor oil once a week and leave it in over night! I've heard loads of good reviews about castor oil for healthy hair/growth and it keeps my hair feeling really smooth.
Love Roxy x