Open Ots Studio.
Click on the 
button and navigate to the Ots file that you would like to
remove an item from.
Right-click on the item that you want to delete and select the Delete Item option. Alternatively, go to Edit in the program menu and select the Delete Item option.
You will be prompted by the Do you really want to delete item " " and all of its associated chunks? message.
Click on the Yes button.
To save the changes click
on the 
button.