Blending grey hairs on dark brown hair!

[Mummy2823]

I'm only 31 but have quite a lot of grey hair. Started when I was early 20s. I tend to have a thick strange right at the front and then streaks throughout my hair. I haven't dyed my hair in 2yrs due to have 2 babies and I didn't want to dye my hair whilst pregnant Incase of any risks. Because of not dying the nearly all of my previous box dye brown has grown out.

Can i put a blonde box dye on my hair to turn the greys a blondey colour?
I don't mind my brown changing a little from it but wondered if it was possible?

Bumping for personal interest

I use Josh Wood permanent dye in the shade I want the main body of my hair to be (as usual wuth hair dyes shades are very dark so for my dark brown hair I choose 'lightest brown')
That seems to dye my grey hairs to differing shades of blonde and brown and looks quite natural as it isn't just one block of colour. My natural highlights show through