Reddit mentions of CAF Outdoor Cleaning SEMPER Quick Dissolve Windshield Cleaner Mix - 5 Pack

Adding to the excellent comment from /u/Zen_Drifter ...

> tire plug kit

Not gonna hurt, but personally I wouldn't bother. They're a PITA to use without having the wheel off the car, at which point you should just swap it for your spare (which you should check, along with your jack and related tools) so you can get to a service center where they should dismount the tire at patch it properly.

Fix-a-flat works as well or better, and is 10x faster which is really important if you're sitting on the shoulder of a 70+mph road! Just make sure to tell the service people about it before they monkey with your wheel. Only down-side is the risk of pressurized cans in high temps, but it's never been a problem for me in 30 years of South Florida temps. (car interior regularly reaches 180°F)

As stated, a 12V compressor is extremely valuable. Not just for emergencies. It'll save you $1.50 in quarters, free you from hassles of faulty equipment, and let you be someone's hero when they really need it.

> washer fluid

This is a tremendous waste of space, and you risk spillage. I used to carry the 4oz bottles of concentrate, but they're increasingly difficult to locate. I've found an even better option is Tablet or Powder concentrates. Be aware these are non-antifreeze! (but you can just dump in a $0.50 bottle of isopropyl to solve that)

> zip ties

Harbor Freight has cheap "larger" sized ties - like 1/4" wide and 3' long - which are particularly useful for holding plastic inner body panels away from tires after damage. (collision with another car, terrain, or fauna) That can mean the difference between a drivable car and waiting for a tow.

I'd also add a bunch of important stuff:

• One of the 12V LiFePo "jump packs" that are all over Amazon these days. Very convenient rescue for a nearly-dead battery, and can be used to charge your phone too. But it may not give you enough juice to start from completely dead, so you still should carry jumper cables.
  
  
• A decent tire pressure gauge. You don't need a high-dollar dial indicator suitable for NASCAR, but you shouldn't trust the super-shitty stick-style keychains either. I like digital ones for convenience, and for ~$10 you can do pretty well with them.
  
  
• Reflective triangles and a safety vest. Also a decent headlamp and/or flashlight, preferably with disposable lithium batteries.
  
  
• Mother fuckin' fire extinguisher - and make sure it's somewhere you can get to it pretty quickly. Stop a big fire while it's still small. But also be aware the chemicals may damage stuff in your engine compartment. (way better than the whole car burning to the ground though)
  
  
• At the very least, a couple of the mylar "shock" blankets. They're super cheap, small, and can save your life if you get stuck waiting out a freak snow storm or something. But ideally some warm clothes, and a blanket or sleeping bag.