Final answer:
Voiding a check involves writing 'VOID' across it and retaining it in numerical order with other cancelled checks for record-keeping and to prevent fraud.
Step-by-step explanation:
To properly void a check, one should write "VOID" in large, clear letters across the front of the check. This indicates that the check should not be processed or paid out by a bank. It is important to retain the voided check with your other cancelled checks, keeping them in numeric order for proper accounting and record-keeping purposes. This is a preventative measure to ensure the check cannot be used fraudulently and to maintain a consistent financial history.