All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
A Muslim must fear Allah and seek to transfer his/her salary to one of the Islamic banks to prevent his lawful money from mixing with the unlawful money of the usurious banks.
If this wasn`t possible then there is no sin in opening a current account in one of the usurious banks under the condition of doing one`s best to withdraw that salary once it has been transferred into that account. Moreover, it is unlawful to deliberately delay withdrawing that salary under the pretext of saving a portion of it until time of need. This is in order not to play any part in helping an institution whose business is founded on usury. Rather, a person must withdraw the whole salary from that usurious bank, then open a new current account in an Islamic bank and withdraw whatever amounts he/she needs and at any time. And Allah the Almighty Knows Best.