Two windshield-related questions...

Anyone know of a windshield polish that works, or are they all a scam? The pitting on mine makes driving at night less than fun when there is oncoming traffic (throw rain into the mix and it gets downright scary). A paint job is a year or two down the line for 'the Bird' and I'd like to wait on a new windshield until then if there's a way to polish some of the pitting out in the meantime.

My windshield sprayer is acting up- the motor always spins when I hit the button, but sometimes it sprays a bit then goes dry, sometimes it doesn't spray at all. Tubes are good. Do the blades or paddles or whatever are in there wear out? Is there a way to open the thing up and fix it? I also seem to recall a one-way valve for sale somewhere that goes in the tube- does the pump need to be primed with water to work and will a valve keep it so?

Thanks!
Tom
NYC