there are some good ways tp prevent the fogging problems.i use a cleaner called anti-fog and one called parker's. both work pretty well. i take a clean lens cloth. i do not use the pens cause they pick up too much grit. at home i use a air duster just like on the pc keyboard.just like x said i have contacted the mfg and they have always stood by the products. i have used leupold, swarovski, and leica. leica sent me a new pair of binocs.