Delete an excel file in your file from your box

1. Right-click (or click the ellipsis (...) on a file/folder and then click Trash. Alternatively, you can click next to the file/folder name to select it, then in the upper-right click the trash icon.
2. Box moves the item to your Trash folder and displays a confirmation message.

For more details on managing your Box Trash, please take a look at this article: https://support.box.com/hc/en-us/articles/360044196093-Managing-Trash 

Best,