If you sweat profusely, a special leather-care lotion should be applied from time to time to leather linings because the salty sweat produced by your feet can dry out the leather, making it brittle and hard. GORE-TEX linings require no special care, but they can be cleaned occasionally with lukewarm water and a gentle soap solution. Also, please regularly clean and condition the leather on GORE-TEX boots as the GORE-TEX membrane will lose its effectiveness if you do not keep the leather uppers in good condition. It is not enough to apply waterproofing or shoe-care spray to intensively used GORE-TEX shoes!