I haven't bought a hat in ages, so I don't know what one should do to clean out the inside of them after purchasing. I don't know how many people have tried it on, so I wouldn't want to catch anything.
Do any of you clean the inside of your hat when you buy it, or do you just roll with it as is?
You could use a steamer, or something like lysol. As long as you don't saturate the bill or dip and crush the crown, it shouldn't be an issue. If it has a plastic bill core, then you could even hand wash some baseball caps.
But really, you shouldn't need to clean a new hat.