I don't know, but it's worth a try! With our front-loader, though (didn't you guys get a FL?), anything you pour into the detergent cup runs immediately into the main washer compartment - especially if it's thin like vinegar (as opposed to thick liquid detergent). When you start a load, the water flows through the detergent cup to wash it all down. So basically it will all end up in the washer pretty quickly. I'd still pour it into the detergent cup, though, because maybe it's something in there that smells.
