While my parents were here, I took my mom to the local leather/biker store in search of battery-heated socks. I'm sure she was the first Indian grandmother to set foot in the place. Anyway, the socks and gloves were over $200 (!) but the woman suggested sheepskin insoles. They use the scraps from making other items like car seats and cut out shoe inserts which they sell for $12 a pair.

My mom bought one pair for herself and one for me, and both of us found them to be incredibly toasty. I can switch them between boots as needed, and the additional layer between my feet and the ground makes a huge difference. They do make the boot/shoe a little tight at first, but then they conform to your feet and are super-cozy.

I know not everyone here wears animal products, but I just thought I'd share.