How can one purify a salary earned from a government company when work tools have been used for personal purposes, and is donating some money to mosques, without specifying the amount, sufficient?

It is forbidden for an employee to use work tools for personal matters without permission. He must return what he took or pay the rental cost for its use to the government company, because public funds have the same sanctity as private funds, or even greater. Donating some money to mosques is not sufficient to absolve oneself of responsibility for these funds, as these tools are considered stolen or usurped.