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I'm sure there would be some way to have a package which unequips all her worn stuff. Alternatively, you could make her equip "dummy" stuff so that it overrides her other gear.
Failing all this you could have a trigger zone with a script to either use http://www.creationkit.com/UnequipItem_-_Actor or http://www.creationkit.com/RemoveAllItems_-_ObjectReference. With the later, you could have a nearby out-of-reach chest to remove her inventory to, and when she leaves the bath room they get removed from the chest back to her.