The vinegar is used up and you are faced with a chunk of plastic that has served its initial purpose as a 4-litre container.
What next?
Use the sharpest knife you can find (“Hold tightly, press lightly”) and slice the bottle into two parts.
In the photo above the left-hand part will make a convenient holder for incoming mail or receipts. Or recipe cards.
The right-hand part will serve as a scoop for potting-soil or, with the cap temporarily removed, a scoop-and-funnel for sand.