For a while now, I've been experimenting with different window cleaners and microfiber towels to clean the inside of the windshield with no luck. Today I just did a quick wipe with a damp piece of Bounty and the windshield has never looked better, very nice.

 

Something else you might try (my dad taught me this one):

Mix 1 part vinegar to 3 parts water in a spray bottle. Use it like windex but wipe it off with wadded newspaper. Works pretty well.

 

I have tried that and I agree it works very well, but I'm not the biggest fan of vinegar unfortunately.