I have a couple of hats without liners and have never had any problem with sweat marks on them.
A goodly % of Akubras are sans liner when purchased (cattleman and snowy river, their biggest sellers).
So liner removal is hardly problematic.
On a side note, one of my lids (probably 1960s) has the plastic insert between the liner and the felt, so your head is on the liner, but the felt is still proteced from your
Dapper Dan Pomade.
