There is a little war going on inside your rain jacket and waterproof boots. Anything that says it has a breathable waterproof fabric is in a constant state of war between water from precipitation vs humidity from sweat. The fabric needs to be breathable enough to wick sweat away, and waterproof enough to keep the water out. In order to do that, these fabrics have a membrane which consists of tiny holes too small to let liquid water enter, but large enough to allow water vapor to escape. Since contamination with oil, sweat and many chemicals cause the membrane to lose its ability to keep out water, manufacturers add an outer layer that is not waterproof, but which has been treated with a "Durable Water Repellent (DWR)" coating to protect that precious membrane.
You know water is winning the war when your feet start feeling clammy inside those waterproof boots, or when your shoulders start feeling cold and wet in a downpour.
The DWR coating is like the wax job on your car, when water stops beading and the surface "wets out" the fabric cannot breath or let vapor escape and condensation will begin accumulating on the inside. This is the point at which you should grab some Nikwax to clean and refresh that DWR layer. Nikwax has created a number of products to help clean and re-waterproof an amazing array of fabrics (i.e. down, wool. nubuck, fabric, leather, etc.). The wash removes particles that act like paper towels in a cup of water, which wick the water from one place to another, and the water repellents replace that DWR layer so water beads and rolls off.
Taking care of footwear can be confusing due to the many new materials used in their construction. Nikwax had solved this issue by creating a general cleaning gel that is safe on all waterproof materials. You might find that a cleaner is enough to win the battle, but if more is needed you can also chose a waterproofing solution that fits whatever material your boots are made from. Nikwax Footwear Cleaning Gel™ is environmentally friendly, non-hazardous, water-based and biodegradable. You do not need to throw your garment or shoes in the dryer or oven to get this product to set, just set them out to air dry! The green top is for cleaning and the purple is for waterproofing. The
on how to use their products.