Cold toes?
Be aware of shoe size. If it feels tight that reduces circulation and this method will not.work.
Also this is not for walking but if you sit like I do, it works great. Hunting or Ice Fishing.

I use the Normal Hot Hands not the Boot variety.
Wear a thin layer of socks. JUST past your toes, on top of your foot, take the Hot Hands ,lay it flat, and place a strip of tape on each side and attach to your sock.
Then add a second sock to help hold all in place.

Works awesome in Pac boots. But for me far to HOT in other boots when I walk.

JW