Originally Posted by Tetranode
It's the middle of summer and I realized my gear reeks. Badly.
I'd put the mitt and helmet liners in the laundry, but that still doesn't solve the odor problem since I can't wash the helmet or the mitt covers. The mitt covers will lose their waterproofing property if I put them in the machine, but I could always look into waterproofing the pair after I wash them.
Focus: How do you deal with your smelly gears?
What I don't see in your OP is how you store them, or what kind of material.
I have not had a problem with my Ski Gear and odor, but my husband's dirtbike gear is another story, entirely. He stores it in a huge rubbermaid tub that does not allow for ventilation.
Some products such as mittens/gloves are made with products that cause sweaty hands, or the material itself generates an odor. If you store your mittens with your helmet, then the odor will marry the two items.
I'd wash the mittens with the product Jpow suggested, and fabreeze the helmet.
Store them separately, in a well ventilated container, and see what happens.