I struggled with this for a long time and it drove me nuts!! Whether this is the right way or not, here is what worked for me:
1. Create a new calendar (I called mine "stuff to delete")
2. Open each event you want to delete. Go to "edit" and switch it to the new calendar you just created.
3. When you're done moving all of your unwanted events, simply delete this calendar. If this makes you skittish, simply turn the viewing off for this calendar.
Hope this helps!