Stainless Steel Insulated Coffee Cup with Lid 350ml 2 "Decent thermal properties, but difficult to clean" Mr Jensen 29 December 2015 I've had this cup for a few months, and have found it's heat retention properties to be very good. It is a good size (not too big), though the narrow base makes it less stable than a conventionally shaped mug. The major flaw I have found is with cleaning. It's advised not to go into a dish washer, but I can't find away to disassemble the lid to clean the working parts inside. Unfortunately, after several months, drinks from it have a mouldy taste that suggests the inside of the lid / mouthpiece need a really good scrub. Is it possible to open this area? Disappointing. A note from the team Thanks for the feedback. If the lid is clicked to the open position you can then use warm soapy water and a washing up brush to clean it, then rinse with warm water. I'll be in touch shortly.