I have a spreadsheet with a lot of numbers. I want to print the
spreadsheet to show someone, but I want all numbers to be x'ed out.
For example, 123 becomes xxx and 1,234 becomes x,xxx.

Is there an easy way to accomplish this?

It would be ideal if I could do a find-and-replace. Alternatively, it
would be okay if I could accomplish this with custom format.

I copied the workbook and did a copy-and-paste-special-values so there
are no formulas, which would otherwise get screwed up by changing
numbers to text.