Hello and welcome @SophieRice1 
You can use the bulk options from the search results to delete en masse. You can add in the advanced filters to get what you need:
And then access the options from the wrench icon:
Personally I’d recommend selecting them individually just to be sure (though you can always undelete any you accidentally clip out), but if you want to ‘select all’ you will need to scroll down to load them all, or it will do them in ‘visible’ batches. 