Salt water.
----
Any water makes iron rust. Rust is iron oxide. It happens when water allows the oxygen to dissolve in it and get to the surface of the metal. Salt water has dissolve salts in it which makes it work faster.
Liquids do not rust, iron does, rust is Hydrated Iron (III) oxide, so the only substance which can rust iron is water
coke will make it rust faster
The cause of iron rust is oxygen and water.
water
Water, especially when it contains dissolved salts or minerals, can accelerate the rusting process of a screw. This is because water provides the necessary conditions for the electrochemical reaction between iron and oxygen to occur, leading to the formation of rust.
An iron nail will rust faster in saltwater than in tap water. This is because saltwater is conductive and accelerates the rusting process by promoting the flow of electrons between the iron nail and oxygen in the water.
soapy water does make nails rust because of the soap mixed with water are two different types of liquids which also makes it faster to rust
soda because it is the most acidic
Modern coins cannot rust, as they are not made of iron.
Iron will rust more quickly in salt water than fresh freshwater. The salt in the water accelerates the corrosion process.