I have an opened bottle of balsamic vinegar that’s at least 8 years old. Can I use it?
My googling suggests yes.
Are you using it for a recipe? Do you have strawberries?
Here’s one thing that amazed me when I started “cooking”. You may already know this, but if not…
Take a strawberry - taste it.
Now take a tiny bit of balsamic vinegar - taste it.
Put a strawberry in a little bit of balsamic vinegar - now taste it.
Couldn’t believe the difference it made.
Anyway - I’d do the strawberry test. If it improves the flavor - and you don’t die - then I’d say it’s still good.
Sure, it’s safe. It doesn’t spoil. I doubt that it would even deteriorate, unless the bottle was left open for any length of time.