We do a simple export from Quickbooks and there is one page of data but the
file size is 3 MB. if I select just the rows and columns that contain data
and copy them to a new workbook and save it the file size drops to 11K.

I copied the sheet to another workbook and it is the same size.
I saved it in every format I can think of. CSV makes it much smaller, but
lose formatting. Binary makes it smaller, but if I save it back as XLS or
XLSX it is large again.
I've tired clearing all unused cell... which takes too long, but doesn't
work. Same size.

I don't know what it is about this sheet. Any idea??

I have Excel 2007.