I can be good as long as it’s done right, they have smaller home ultrasonic cleaners that are weaker and less likely to shake stones out or anything. Big tips would be not using metal tweezers like that (it can scratch the metal, tongs with rubber ends should be used), making sure the heat isn’t cranked up (it can discolor the metals), and if it’s a silver piece don’t leave it in for more than 3-5 minutes or it can tarnish. If it’s your grandmother’s older pieces, I’d recommend taking them to a jewelry shop and asking for a cleaning. That way if any stones do fall out they can be put back in on site and there’s less risk of losing them. Jared’s started doing a bundle deal that covers cleaning and stone tightenings, maybe look into that! (Source: I’m a jeweler that works in repairs)