Unlike gasoline-powered cars, my Tesla is rarely at a gas station. The chargers in Tesla's Supercharger network are occasionally located on or near gas stations, but they're more likely to be at a hotel or in an industrial area, meaning you're not going to find a squeegee and water bin for cleaning your windshield.
To solve this problem, I keep a roll of paper towels and a can of Zep Foaming Glass Cleaner in the back of my car. While the car is charging, I spray and wipe the front and side windows. I've found that bug residue easily wipes off; only the largest of bug stains require a bit of elbow grease.
A recent 3,500 mile road trip (more on that in a future post) really put this system to the test, and it worked quite well—each time we charged the car, we left with a nice clear view…which lasted for all of a few miles, of course.
The other advantage to this method is that it's way less messy than water and a squeegee; it's easy to keep the spray exactly where you need it. This works so much better than the old method that we've put another can in the back of our gasoline-powered car—no more squeegees and water (of questionable cleanliness) for us!
This won't work well if you've got a large SUV, though, as you need to be able to reach across at least half the width and the full height of the windshield…another reason to stick with sedans!