You can delete delete the entire board, content from the board, or remove uploaded attachments from the board.
Deleting a board
To delete a board, go to Board Settings, and click "Delete". Only Board owners may delete a board.
If you are not the board owner you can click "Leave board" to remove it from your Boards Overview.
Please note that if you delete a board, deletion is permanent and it can not be recovered. Try Archiving a board if you think you will need it again.
Deleting from the board
To delete content from the board itself, you can use Select Mode, and select the object and press Delete or Backspace on your keyboard, or use the Trashcan icon that appears in the toolbar.
You can also use the Erase tool in the drop down menu of the Select tool. Once in this mode, click on any item you would like to remove from the board.
Please note, when deleting a document or image, this will delete it from the board and from the Board Sections Outline, but it will still be available for download from the Export files dialog.
Deleting from Export files dialog
You can also delete content from the Export files dialog. To access this dialog, click on the Board menu and select Export files.
You have the option to download an attachment by clicking on its image preview, or to remove it by clicking the remove button in the upper right corner of the file preview.
A popup will ask you to confirm that you want to delete the attachment, as deleting is permanent and cannot be undone.
Please note, deleting a file from this dialog will not delete it from the board itself.