how does one "easily" remove the sweat ring caused inside a baseball hat?

Something that has worked on sweat stains in my experience has been Zote (pronounced "ZOH-tay") soap. It's a bar soap imported from Mexico and is intended for doing laundry by hand on a washboard, but you can also dissolve it in water to use in the washing machine, or use it for dishes or bathing. (I wouldn't suggest using it in the dishwasher, however.)

Put a good stopper in your bathroom or laundry room sink. Put the bar of Zote at the bottom of the sink right where the water hits out of the faucet. Run the faucet full blast on no hotter than lukewarm until the sink is several inches deep. Let the soap soak in the water for about half an hour; the water should look milky by then. Dunk the hat in the water and swish it around until thoroughly soaked. Rub the soap bar on the sweatstains until you work up a good lather. Put the soap aside. Rub the soapy stains with a toothbrush, going over each part several times in a different direction each time. Submerge the hat in the sink and let it soak for an hour or two.

Take out the hat and see if there are still obvious sweat stains. If there are, scrub again with a soapy toothbrush and return to the water to soak another hour, or if the water looks very grey, make a fresh sinkful of milky Zote-water to soak in.

When the sweat stains are either no longer visible or much less pronounced, drain and rinse the sink, rinse the hat under the faucet, and fill the sink with fresh, clear water. Soak the hat another hour to get the soap out. Rinse again under the faucet, then put the hat in direct sunlight to dry, with the location of the sweat stains facing the sun. (It's the ultraviolet that activates the optical brighteners in the soap, making whatever is left of the stain nearly invisible.)

This is the same technique I have taught over 138,000 men and women in 157 countries to successfully treat their excessive sweating condition over the past 7 years!

Remember: Watch the whole video, as the ending will pleasantly surprise you�

Top rack of the dishwasher, don't let it go through dry cycle. Let it air dry in your room.

Presoak with laudry soap and wash. Do not dry in dryer ...will shrink it