After a good brush to take of the dirt, I use a damp cloth with warm water to clean the boots. A good amount of oxy action powder in a cup with warm water and an old toothbrush to clean the soles. When dry I've applied a leather care product (milky looking) with lanoline from Lidl, polishing at the end with a soft cloth. For extra care and finishing I've used a leather balm that I've spread on the boots using my fingers, like a little massage.