I thought I heard that its ok to use a coffee pot in a non-kosher home, but I could be mistaken. Does anyone know?
See the Aruch HaShulchan 325:21 where he finds a reason to permit Jews to drink tea in the homes of their non-Jewish neighbors on Shabbos, even when the non-Jew prepares the tea on Shabbos. In particular when a samovar is used, he finds even more reason to be lenient about this practice. So it seems the common practice was to drink tea in non-Jewish homes (even on Shabbos!) and presumably the same would apply for coffee.
Although I cannot give sources, I can give reasoning to be able to use it.
- Plain coffee beans are kosher. Even if the beans were flavored, my Rav told me that the vast majority of flavors in America are kosher (even grape!) and are not a concern- certainly after the fact.
- It is far-fetched that anyone used the carafe for anything but coffee, and on the off-chance they did, that product was probably kosher even if it didn't have a hechsher (take your pick of chazaka or sfeik sfeika)
- It is pretty much impossible to render something treif in a sink. Do you know if the water was hot? Is the water running through the pipe of a halachik status to cause a problem (irui kli rishon? Even if it does, can it treif up the carafe (machnis and motzi at the same time)? Was there even anything non-kosher touching the carafe? Soap makes the tranferring food taste bad (taam lifgam). Can glass even become not kosher?
Dishwashers are more complex, though I think there is enough to mitigate the concern there as well. But since you should ask your rav anyway, this information is for you to be informed when you ask.
I don't see why this person's coffee pot is any worse than the coffee pots/carafes in non-kosher restaurants. It is widely accepted that one may buy coffee in non-kosher restaurants.
I am aware that the CRC presented some issues with Starbucks washing procedures leading them to forbid the purchase of coffee if food is also sold there. If the CRC meant this to apply not only to Starbucks in particular, but to restaurants in general, then it can be considered a machloket CRC-OU.