How to go from dyed red back to my natural colour?

I just dyed my hair for the first time from natural blonde to bright red. Thankfully it was a wash out colour, but soon the red started to fade and my almost natural colour was starting to come thro on the bottom while the top of my hair was still red so i redyed it. I didnt check whether the dye was semi-permanent or permanent (i got my friend to do it at home for me) but we had to mix the colour ourselves and then put it on the hair with a brush. Now my hair is "Scarlet Copper" and i really wish i had my natural blonde back. SO my question is does anyone know how i can get my natural colour back with the least amount of harmful chemicals/proccesses used (im not worried about how long it will take just as long as i dont damage my hair anymore =D)