Giving unwanted things to others will not only mean you're doing your bit for charity or get you in others' good books, it will rid you of junk you wouldn't otherwise part with. Charity shops are always looking for clothes, gifts and unwanted items. And if you give to friends and family you can always ask for it back!
So do you really need 2 copies of the same book, that old tea-set and all those socks that don't match? Go through everything with a fine tooth-comb and be ruthless! Remember that all that stuff you don't use is only taking up valuable space.