Reuse bad barrel?

[Bigvalveturbo]

So a friend gave me a barrel (10 liter) that had elderberry wine in it..it went BAD! very vinegary and smells a bit acetone now that it is empty. But definitely has a sweet smell too. Reuse? (I was thinking a sugar wash) and should i rechar?

Also have a 20l with cider that went by...

I don't want to waste the runs but am curious too...