I don't remember when RainX came out, but it is wonderful stuff. Up until about 25 years ago semis had air wipers which weren't much better than vacuum. Another trick I learned in my many years of driving a truck is that Coca Cola dissolves bugs. When my windshield got to where I couldn't see, I bought a bottle of Coke, shook it up and spewed it on the windshield. It worked well. Of course, now it is a DOT violation for not having fluid in a windshield washer.
