You deleted "Animated" in the properties? Clever. In cases like this, when I've got too much effort involved to throw the model away, I just started the animation at the earliest point in time at which the model is not distorted. Instead of an animation that runs from Frame 0 to Frame 200, I'd have one that runs from [let us say] Frame 45 to Frame 245. Deleting keyframes never worked. Duplicating them and moving them back didn't either. You just have to ignore anything prior.