Buy a box of discount store tea. Common and cheap black tea is fine. Bagged or leaf are okay. Brew up strong batch a quart with ten bags and boil a long time. Let cool with the bags, leaf, still in. Strain out the leaves or remove the bags. Store in a sealed jar in the fridge.

Dilute a quart or so to a little over a gallon. You can use it lukewarm or dilute with hot water and use warm. Don't use so hot you hurt yourself.

Soak you feet in this brew for half an hour a couple of times a day. A good time to read the newspaper or watch TV. Don't wash it off. Just towel dry and move on.

Stored covered it can be reused for a couple of days.

The tannin in the tea shuts down your sweat glands and allows the natural flora to rebalance. Done twice a day for a week or so you should see real results and you can back off to once a day. As the flora normalize you can back off to once every two days.

Some people prefer to use the tea concentrate and to paint it on and let it air dry. This can be handy for trips where the whole soaking thing can be inconvenient.

Also it pays to look at footwear. Wearing the same shoes every day can make it worse. Rotating footwear so they can dry out can help. Natural fiber socks and changing them often can also help.