I'll probably catch **** for this, but I have quick dipped them in muriatic acid.
Basically a 60 second dip and then flush well and it worked great.
Leave to long though, and you don't have a carb any more.:D
And if vinegar worries you don't use muriatic acid.
Has anybody tried anything else. Evapor Rust maybe. Just trying to think out side the box. Don’t think I would want to soak a carb in Apple Cider Vinager. Thoughts. Kim