In the July issue (page 96), I suggested a technique for partially hiding numbers in a spreadsheet that you need to keep private— such as Social Security numbers. Steve Gordon, CPA, internal auditor at Northwest Natural Gas Co., Portland, Ore., pointed out a weakness in the idea. He said that the concealed data will come out of hiding if you simply copy and paste the information into another worksheet. One way to improve safety when you protect the sheet (Tools, Protection, Protect Sheet) is to be sure to deselect the checkbox next to Allow all users of this worksheet to: Select locked cells (see screenshot above). Recognize, still, that a determined person can usually find a way to overcome Excel’s security.