vinegar is acetic acid which will give you the corrosive effect and remove the rust from what I can find in a quick search online about malt vinegar it appears that it is fermented so I doubt from a chemical reaction standpoint that it will help with the removal of the rust
Malt vinegar is very popular in England. It's made from fermented barley and grain mash, and flavored with woods such as beech or birch. It has a hearty flavor and is often served with fish and chips.