When looking at the events list in the Editor CMS, you have the option to search by name and/or date (see image below). You also have options to filter events, including by “Data Source”. Typically, filtering by data source and searching by keyword(s) will help you find any group of events you may want to reject.
To use the bulk reject feature, select checkboxes next to any events from the list and then click “bulk reject”. You can also filter events by category, data source, and keyword, and then check one box at the top to select all.