How to decaffeinate your Green tea.  Heat the water according to the type of tea (water shouldn't be heated to a full boil for all types: ie Green Teas & some Black Teas - see below.)

All you have to do is steep the tea for 45 to 90 seconds in hot water and then pour off the liquid.  Next, add more hot water and steep as you normally would to brew a cup of that tea. Up to 60 -80 percent of the caffeine is released in the first infusion of water so only minimal amounts will remain when you add water the second time. This method eliminates very little of the tea's flavor and aroma. This results in a caffeine content of about 20 -40 milligrams, whereby, if you simply make your tea & let the water steep for 3 or more minutes, the caffeine content will be from 50 - 100 milligrams.

If tea caffeine bothers you, I highly encourage you try out this method. But beware, the 80 percent figure is probably spurious. Also, the so-called Hot Wash Method will remove the antioxidants and theanine, alongside caffeine.By all means try the Hot Wash methog - Just be aware that it won't work for the same for all teas.