In search options you need an "exclude" box to check and form to fill. Today I wanted to clean up my mailbox and almost 200 emails from a bank, some of which was important but most was basically spam with offers. It would have been nice to exclude any mail with the word "payment" (like "payment required" and "thanks for your payment') and having an easy way to only tag the spam without having to scroll a couple lines at a time and select each individual one.