Reducing balsamic vinegar typically takes about 15 to 30 minutes, depending on the desired thickness and intensity of flavor. To reduce it, simmer the vinegar in a saucepan over medium heat, allowing it to evaporate and concentrate. Stir occasionally to prevent burning and achieve a consistent reduction. Keep an eye on it, as the process can vary based on the amount of vinegar and the heat level used.
You cannot usually substitute balsamic vinegar for cider vinegar. The flavor profiles are quite different. However the chemical properties are similar, so the actual answer depends on the particular situation.
no. it is a vinegar so it preserves itself
1 day
It doesn't.
it takes up to 5 to 7 days to turn rubbery.
yes egg shells can disintegrate in vinegar.
2-5 days
about 9 days
If they are an alloy, they will eventually rust.
About 2 to 3
yes
wash them in vinegar to make them shine for a long time