Maybe you can use an Excel add-in (not tested in xl2007) that lists all
Styles in a workbook and along side that list all unused styles.
It allows you to delete all unused styles from the workbook.
(custom number formats can also be listed/deleted)

For those interested, the free "Formats & Styles" Excel add-in is available
(via email attachment) upon request.
Please provide a real name and geographic location.
Included is a Word.doc install/use file(non xl2007).
Remove XXX from... james.coneXXX at comcast.netXXX
--
Jim Cone
Portland, Oregon USA


"Maureno"

wrote in message
Since Excel 2007 can only store a limited amount of formats, I continuously
have issues where my big files crash. I've found that this issue is due to a
massive amount of Cell Styles that get created everytime I copy/paste between
2 instances of excel (ie: using multiple monitors) or when I copy in a tab
from another file.

My question is, how can I delete all these Cell Styles at once? I can
select them one by one from the Cell Style drop down in the Home menu under
Styles. This is unmanageable when there are thousands of these.