NGO JFSA collects clothes to help a school in a slum district in Pakistan.
Info provided in Japanese only.

http://www.jfsa.jpn.org/index.html
How, when and where to send
http://www.jfsa.jpn.org/iruiinfo_ippan_annai.html

Suits have to be dry cleaned to be accepted.

For shipping, I recommend "Yamato Bin" by Yamato. It's a much cheaper alternative for "Kuroneko Yamato no Takkyubin". They charge by weight or volumetric weight only, regardeless of the number of the packages.
http://www.kuronekoyamato.co.jp/yama...kin/tokyo.html
Delivery date is not guaranteed but just a couple of days more than their regular service.

Malala Yousafzai would smile.