IF you want to delete multiple items . You can do it this way
export CSV => Edit CSV ( Delete all the entries you want ) => Purge All in Sku Grid => Import
ALWAYS have a copy of the original csv file in case something go wrong
WE DON'T SUGGEST THIS FOR UNEXPERIENCED USERS
Important: Excel may screw up your ebay item ids by converting them to scientific notation, please check that it did not happen when exporting back to CSV (you need to format column with item ids to avoid that).
If you have compare urls in the CSV, you will need to add column called autoCompare and set it to 1 on all rows where you have compare items