I make many spreadsheets that contain a CUSIP column, which can have
leading zeros. Excel helpfully strips these off, rendering them
unreadable.

Normally I address this by putting a quote in front of the number to
force it to be a string. However, I notice that the quote is actually
exported if you save it as CSV.

So I can't use a Format to do this because that gets killed off in the
CSV form and the zeros get stripped, and I can't use the quote because
it doesn't! Any suggestions?