Great question! You cannot delete specific emails in your Rollup, but you can delete emails in the "Unroll.Me" folder in your email client.
Where to find your "Unroll.Me" folder in Gmail:
Please note that deleting an email from your "Unroll.Me" folder only removes it from that folder. It does not unsubscribe you from it, nor does it remove future emails from landing in your Rollup. If you would like to unsubscribe from an email, or remove it from your Rollup altogether, please follow the steps here.