You should pay 2.5% of what you have of gold, silver, banknotes or commercial commodities, if each item reaches the Nisab (the minimum amount on which Zakah is due) independently or by adding it to other money or commercial commodities after a year has elapsed.
It is not permissible to pay Zakah to UNICEF, (Part No. 9; Page No. 440) since their activities and expenditures are not designated for Muslims. It is, however, permissible to pay it to the Afghani Mujahidin via a reliable person who can hand it to them.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.