So once a year a Muslim works out 2.5% of everything they own, and
hands it to an approved organisation to use for charitable purposes.
Muslims call this Zakat, and it's the third pillar of Islam.
It's not a religious tax, as some people (not Muslims) say; it's an act
of worship, and it's something that pleases God: in fact in the Qur'an
you'll find that prayer and zakat are frequently spoken of together.
Zakat is an act of worship that goes directly to making the world a
better place for people who are up against it.
Paying Zakat also purifies the 97.5% of your wealth that remains, and
you can use this as you wish with clear heart. You can use some of it
for gifts to charity, but such spontaneous charity is called sadaqah,
not Zakat.