Just found this. Maybe adding salt to the vinegar at a 1qt vinegar to 2tbsp salt ratio (1gal vinegar to 8tbsp salt) would improve it's rust-eating ability.
http://needlebar.org/nbwiki/index.php?title=Rust_Removal
This method appeared in the 1990 bulletin of the Society of Ornamental Turners:
Soak item in a plastic, glass or enameled tray in a quart of vinegar mixed with two tablespoons of salt. This makes a dilute solution of hydrochloric acid strong enough to lift off the rust but harmless on hands and clothes. For light rust, soak for a day, for heavy rust, two or three days.
Remove and rinse in warm water and detergent. Most of the rust will come off with a rag. Scour rest with steel wool.
Finish by wiping with an oily rag or spray with WD-40.
The solution can be re-used by adding a little salt. When it becomes very dirty, throw it out and start over. Keep a lid on it to prevent evaporation.
I just bought some evapo-rust today from HF. I wish I would have found this first.