Just crack it open and either clip the leads to the "speaker" or put a few layers of tape over it. I too hate appliances with loud beeps - or the new annoying trend of playing songs (usually from the Asian manufacturers).

Love my Breville toaster oven though - thing is so stinking versatile and by far the best of any I have ever used. We use it as an oven far more than as a toaster. Perfect for heating/baking most stuff without heating up the entire house like the regular oven does. We have the one that also has the air fry mode - use that mode all the time to cook vegetables that are delicious and a lot healthier too. Did I mention we really love our Breville toaster oven? And to think I originally chose it because it was the only one I could find that had a stinking light inside?

My microwave used to beep 6 times when finished.

Even if you opened the door it would still do all 6 super loud beeps. It became a race to get there with one second left to stop it.

Also every press of any key would emit a loud beep. Stupid.

So I opened it up and snipped the stupid buzzer a while back.

It's so much nicer to have a silent microwave now.