In our application we have an option to void and unvoid a worksheet(make it so it doesn't matter for reporting, etc). What would be a good icon to represent this action?
- Void: A ghost-like (faded) version of the worksheet icon (if you already have one)
- Unvoid: A solid version of the worksheet icon
They'll imply that void worksheets are passed over during reporting but still exist.
Maybe the icons should have an action, like arrows depicting that the solid version becomes the ghost-like version for the "void" icon and the opposite for the "unvoid" icon.
In any case, I advise you to make up several sets of icons and present them to your users inside the application during usability testing to verify which set is the most understandable.
Use a checkbox with the label "include in reports" or similar.
I can't speak to your overall design (since I've not seen it), but icons often hurt usability while a checkbox should be much more easily understood. This does not strike me as a feature that will be used often, and therefore does not need the space savings an icon provides because it doesn't need to always be shown.