Or, since it is hard to control steam, but easy to control a spray bottle, what if someone sprayed the bottom half of a hat, gradually and evenly lightening the spray as it approaches the top of the crown and then dried it with a hair dryer? Would that result in reverse taper, especially when combined with the lampshade trick?
I would try it and find out myself, but I don't want to risk ruining one my hats. I'd rather somebody else ruin theirs first.
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