If you were running Windows, the answer would be to open the sheet in Works and save it in an
Excel format. I don't know if that will work with a Mac or not.
Well, the deluxe route would be to use Dataviz' MacLink Plus, which
will do a great job and keep as much as possible intact.
Another way to do it is to convert them to another format using
Works, e.g, SYLK. I don't know if Works 3 could save as Excel 2.2 or
later, but if so, that would be the way to go.
You might get some other ideas at the
microsoft.public.mac.office.excel newsgroup.