You don't have to remove them individually. Just press CTRL-Z to undo the insert multiple.
 
Noel,
 
That is only applicable if you have performed no other task after assigning those effects to the FX Bin. If you had perform other task you will then have to erase all those performed tasks just to undo adding those effects to multiple tracks.
 
I think just how you can press CTRL to add the multiple effects one should be able to remove them in one task as well. Its just a suggestion it's really not a show stopper but thought it would be great to improve efficiency.
 
Glenville