Try adding this to a browse url. It's not the most convenient method, but it was easy to implement according to another thread. This thread has "multiple" in it for a reason.
I even wondered about that , and still did not get it immediatly. Maybe because the exlude feature for one tag is not really advertised. So I never came across the question, how to do multiple exclusions, since I did not even know, how to do a singular one.