I always threw away the oil cap: a colleague explained to me what it was actually for.

Avoiding Oil Splatters and Waste
You’ve probably already poured oil into a pan or onto food you’re cooking, only to accidentally squeeze the bottle too hard, pouring too much oil. The result? You end up with splatters everywhere, including on your clothes and the stovetop.

In this case, simply remove the ring and replace it upside down to prevent any risk of waste or splashing. This will save you money and prevent this type of accident.