However when the comments are nothing but SPAM...
I have recently needed to delete 100+ comments from my blogger account. Unfortunately blogger only allows to delete one comment at a time. This is really not helping when I need to delete 100+ comments.
The trick is to use a browser that supports tabs (almost all of them today) and to middle click the basket icon near each comment we want to delete. It will now open in a new tab:
We still need to approve the deletion in that tab, but at least we do not need the extra clicks of returning to the original post and finding the next comment.