When you use your saddle soap dont use water with it.. the last thing you want is more moisture. The best leather soap is in the spray pack. (i am a horse rider as well as a biker) You can whip down your leather with a damp cloth first then dry @ room temperature. Then apply saddle soap..
There is a anti-mold product I got from the Saddlery Warehouse for my bridles that kept getting mold on them. It seemed to work quite well.. It was in an orange container and has a lot of German looking writing on it. I think it was about 20 dollar. Make sure you store your leather somewhere warm which will help. Not in the back of the wardrobe in a room that is shut up in the cold for most of the winter.
Bookmarks