This was widely used at my hometown in China and my parents and grandparents all drink it. Here's how:
When I eat mandarins I peel the skin off. I keep the skin and leave it to dry. I normally leave it for at least 1 day at our air-conditioned office. Then I put it in boiling hot water just like tea, and drink it when I can drink it. It smells nice either warm or cold. When I finish drinking the water I just keep refilling it with new boiling water so the peels from one mandarin can last me at least one day (I drink at least 2 litres a day at office). For the safety of my stomach I don't normally use the old mandarin peel that's been used the day before.
Here you go, free refreshing tea!
I've got a lot of lavender in my yard and wonder if I can make lavender tea as well?