Issue I had with #TravelMug / #ThermoMug "how to clean #tea stain" solved yesterday. Replacement for mug "broken by curriosity" arrived and while itself being dishwasher safe it's manual contained item advising
"To remove stubborn dirt, use dishwasher detergent/tab with warm water and allow to soak in. Then rinse with lots of water"
It worked like a charm! Thank you #Tefal !