lafindesiecle, it definitely depends what on you're starting off with which is dyed brown, not so much natural color. but once you get back to blonde, it should be so much easier on upkeep. i agree with diesanni, definitely better to go lighter gradually. it's not impossible to do it quickly but it's hell on hair.
it probably won't be quick but if your hair is not too long it'll be faster. my hair was super long (below chi chi's), the upper half to two thirds or so is not hard to get to blonde. my hairdresser did heavier highlights each time i was in the salon. the ends are a challenge since it's old hair and processed the most. baby trims are the way to go when you see damaged ends, don't let it travel upwards
Pengy, Kenya might just do the trick! natural salt water / sea salt and sun bleach