For many years, like once a year, I pour a bottle of Techron in our cars' tanks before a fill up. Take off the cap, poke a hole in the foil seal, enlarge that hole, stick bottle in the filler until it is empty, pull it out, fill with gas. Not complicaed. Tried that last night and the bottle sort of hung up going into the filler tube. Then it didn't empty fully (maybe 1/4 left at that point), pulled it out, where it again scraped on the filler tube, rotated it, put it back in. Did that a couple of times and it still had fluid in it, and finally also noticed that the glue holding the foil seal was dissolving, with the foil just barely hanging on. Luckily I was wearing nitrile gloves and was able to scoop the loose foil out with a pinky and then pull it off completely. Then the bottle finally emptied completely. Had I not noticed and removed it the foil probably would have dropped into the tank. I don't recall previously doing anything but cutting the foil and bending it out of the way, it was never the kind that had like a tab on the side so that it could be pulled off, and it always just emptied completely on the first go. Note, the tank took a fill of 7.7 gallons after this, so it wasn't like it had gasoline way up in the filler neck.
