It's bloody hard to get rid of a lot of stuff. I had a great leather sofa, about 15-20 years old (inherited from my grandparents) still in great condition, but I couldn't get rid of it at any price and none of the charity shops took it because it was missing some fire hazard label (sigh...). Same with almost everything: I sold my 2-year old £1,200 mattress for £50 (and I had to practically beg to guy to take it, because it would have been a complete shame to chuck it). Washing machine, fridge, all the "little stuff" (cutlery, books, DVDs, what-have-you). I ended up putting a lot outside "free stuff" and that got rid of a lot.
Actually the only things I managed to sell was an IKEA sleeping sofa and an IKEA dinner table set.
That said, since then I found that actually finding good stuff isn't always easy.