After you have thoroughly cleaned your boots apply the water-proofing impregnation spray while they are still slightly damp. The boots leather pores are wide open while they are damp and that allows the impregnation treatment to penetrate deeply into the leather. Regular applications of an impregnation spray are recommended to keep water and dirt from sticking or soaking in.
It�s particularly important because soaking wet boots lose their breathability, which affects their ability to regulate your foot�s temperature. Please note that a water-proofing treatment needs 24 hours to fully take effect and you should spray the boots from a distance of 20 - 25cms.