My last post explained why I like my self-heating mug so much, but it ended with a well-deserved kvetch: The entire mug becomes useless when a pin on the charging coaster gets stuck. If you Google charging coaster pin, you'll see complaints from all over the Internet about various brands that all have the same problem:¹
One of the pins gets stuck, and no amount of prodding, poking, beseeching, or percussive maintenance will cajole it back into place.