Stickers on your car's windshield, such as the ones you need for parking or registration, are notoriously difficult to remove later. Redditor wewtaco has an ingenious solution: use mobile phone screen protectors between the windshield and the sticker.
Photo by Andrew Turnbull
It's clear, so the parking cops won't mind that it's on there, and most screen protectors are designed to be taken off relatively easily.
That's certainly a lot cheaper than some of the dedicated windshield sticker-removal solutions out there.