Remove insoles and the laces too if they are very dirty.
Outside: Brush off any dirt every time you’ve worn the footwear. If the dirt is hard to remove, rinse the footwear under running water. Special leather cleaners should be applied if nothing else helps. Soap damages the impregnation and most types of leather.
Inside: Leather and textile linings (as in most GORE-TEX®boots) are best cleaned with a sponge or a soft brush and fresh water. Do not use hot water.
Drying: Thoroughly dry your boots after cleaning in a well-aired, dry and shady place with their tongues wide open. If really wet, stuff leather-lined footwear with paper and exchange it several times. The same applies to GORE-TEX ®boots which dry faster and more effectively with paper (toilet or kitchen paper - never newspaper). Also here it is important to exchange the paper at least once every half an hour.
Please note: Never keep wet or damp shoes in non-aired and humid places like plastic bags, car boots, basements etc. Never dry boots near an oven or over fire or any other source of heat. The leather will burn, turn brittle, dry and crack. Another downside is that the entire shoe can lose its shape.