The method shown allowed me to use lightweight breathable boots for a two week
May trip in the Tablelands of SEKI where we had wet snow travel the entire time.
Note especially the insole INSIDE the bread sack and the tuck tape over the top
of the instep grocery bag. This will allow several days use out of a bread sack without
your toe going through the bag. The duct tarp lasts through several days use too.
The neoprene sock worked as a VLB and as an inner sock as it was fleece lined. It and
the bread sack kept the insole and wool rag sock dry as they were sandwiched between
the waterproof layers. A bit of perspiration did make it through the neo sock, but
was such a small amount that it made no noticeable difference. I would sleep with
all the socks in my bag at night, and they were usually dry by morning. I had to
turn the neo socks inside out at night for them to dry.
I have done the same thing with bread sacks replacing the neosocks, worn over thin liners. Tape over the instep again helps prevent the toes
One of my hiking partners used bread sacks with wool socks and tevas for his snow camp
Link to a good description of the use Vapor Barriers in cold weather hiking.