Here are some simple tips that can save you many hundreds of pounds in replacing rusty tools. Tools get rusty because when left in damp conditions, oxygen in the water comes into long-term contact with the metals in the tools and oxidation occurs. Salt water is even worse for tools because there is sodium present too, which speeds up the process of oxidation.
So, by forming a waterproof barrier between the metal and the oxygen, we can save our valuable tools from rust. A simple way to protect your tools from rust is by applying a barrier of oil or wax. After using a bladed tool, rub the side of a candle along the blade to protect knives, scissors, shears, saws and all cutting tools such as secateurs.
This is also good for hammers and any tools with non moving parts. If you wish to protect moving joints, penetrating oil (mineral oil) is a good protector, (although messier that wax).