Some sheets in our spreadsheets are locked for editing to make sure that certain underlying formulas aren't accidentally deleted. If you simply need to copy data, you may have gotten the password message when right clicking on a cell. Instead, simply ctrl+c to copy.
If you would like to edit or remove data, we recommend either using the filter option drop down located at the top of the column next to the heading, or removing data from a file before importing. If you choose the latter, it may be easier to import it into a another (new) spreadsheet first, remove data, save as the same file type, then re-import into the spreadsheet.
If you want to add your own calculations/data to a spreadsheet, you can still do so by following these steps.