I used to wear pack boots for 8+ hrs sometimes.
Those felt liners soak through with foot sweat and sometimes would freeze to the bottom the boot, Id have to thaw the boot enough to pull the liners out to dry them.
After some time I washed them to get the foot sweat out of them in the washer with my coveralls.
After a bit of soaking up so much foot sweat they stink like a old stinky saddle pad.
Eventually they wear out and you have to buy replacements.
Its best to take a dry set of felt insoles, liners and socks and swap them when your perspiration soaks em.
Then I switched to bunny boots.
Dry socks and a dry washcloth help to swab them.dry at changeup.