I've enjoyed hiking my entire life but I have one huge problem. The skin on my feet is extremely soft and sensitive. I wear good wool socks with properly fitting boots and change socks during long hikes. Still, if I am going to be on the trail for a few days in a row, I will develop numerous blisters on my feet.
I have read some suggestions in the past, like an alcohol based solution that mildly dries the skin, and can help harden skin over a long period of time. This is supposed to be dangerous if you dry the skin out too much though. I try to walk barefoot on various surfaces when the weather allows to toughen my feet up with some success.
What are other methods that are safe to harden the skin on your feet? This does not need to be a quick remedy.