I haven't faced a busted WM scenario for some years but I would like to think that if I needed to de-funk a pair of undercrackers without one then I would sprinkle them with baking soda and then spray them with vinegar to get it foaming. I'm obsessed with cleaning stuff with baking soda and vinegar, it's magic. When you see how effectively it peels off a layer of stovetop crud, you'll be confident of its underpant freshening chops. Then again, everyone's underpants are different...