This statement tells me that whoever wrote it has never cleaned a headlight. The modern plastic headlight assembly is a sealed unit and can't be taken apart without destroying it. If the unit has leaked and is dirty on the inside, that's it. Replace it or live with it.

Also, the whole baking soda thing is 'sound good' BS. For $12 you can buy a bottle of professional abrasive compound that will clean a hundred pairs of headlights.

I've cleaned dozens of lenses that have been 'cleaned' by kits or homemade BS like the above. All those kits and methods do is make it easier for me to sell my service. Thanks TV guy! Thanks internet BS!