I was rinsing today that I use at work. I removed the screen and thought to give her a good rinse before she's away for the weekend. I slid a paper towel up under the rim and wow - there was a lot of tea in there! Not sure how long it was there

I have a different one at home that cleans really easily. That is an often understated factor to consider when buying. You can see why the simple gaiwan is so effective (though I don't use one for sencha).