I've found that nothing removes it but abrasives.
Alcohol doesn't work, Invisible Glass cleaner (which is diluted acetone) doesn't work.
What does work is glass cleaner with some kind of abrasive, the most common is aluminum oxide. Rain-X sells a glass cleaner under their brand that contains this and I've used it before, it will remove Rain-X. It comes out of the bottle like a thick, soapy gel, rub it on the glass using a microfiber or terry applicator. Watch out when you use this though, hosing it off is not good enough, it leaves a light film that sticks to everything. A single pass with a car wash mitt is all that's needed to remove the film. I usually lump the glass polishing in right before doing the car wash to make sure I get all of it off.
Alcohol doesn't work, Invisible Glass cleaner (which is diluted acetone) doesn't work.
What does work is glass cleaner with some kind of abrasive, the most common is aluminum oxide. Rain-X sells a glass cleaner under their brand that contains this and I've used it before, it will remove Rain-X. It comes out of the bottle like a thick, soapy gel, rub it on the glass using a microfiber or terry applicator. Watch out when you use this though, hosing it off is not good enough, it leaves a light film that sticks to everything. A single pass with a car wash mitt is all that's needed to remove the film. I usually lump the glass polishing in right before doing the car wash to make sure I get all of it off.