make the Yahoo email filters work properly
I've set lots of filters, yet lots of spam emails still get through, instead of being sent to the deleted folder. Those filters are obviously not being acted on!
As you are deliberately not applying the filters, one imagines you don't want to stop spam.
If you really wanted to stop spam, you could make it so that we could set a filter to bounce emails from nuisance spammers, ... to fill their inbox!!