Tool tip. Go to all comments, ctrl+click on the trash can. This will open a new tab where the comment has been deleted, but without inconveniencing you while you delete stuff. Alternately, get a mouse, click on the can with the mouse wheel, same think happens, but you can work slightly faster.
When did it stop working, exactly? Because if it is past the 'open trash can in new tab', you need to hard refresh afterwards. If it is before that, I guess you might not be using a browser that supports ctrl+click as new tab.
So, assuming you don't have a browser that supports it, which at least both Firefox and Explorer does. Then there's the more slow way, right clicking and opening a new tab manually, but the going is still them same: You get to delete the comments without being redirected while doing so.