Try advertising your clothes on your local *freecycle* group. People post about what they have that is too good to put in with the rubbish or what they are looking for. The only condition is that it must be for free (ie no charge) and no animals. Ever since Boo mentioned this group to me, I've got shot of loads of unwanted stuff (from vintage hi-fi to a little vacuum cleaner and lots of stuff in between). You post an *offer* and then local people who are interested in taking up your offer will email your user account on freecycle which gets passed to you.
Here's a typical Offer:-
OFFERED - Ladies Clothes Size 12-14 Suburb/Area, Mytown. Have large quantity of ladies dresses, tops, shorts, etc, to go in one go. Unable to deliver, sorry.
Here's a typical Want:-
WANTED - Blinds for conservatory (previous owner took them with her), 2 No 6ft x 4ft windows. Can collect.