Shalom Rabbi, I have a Teflon coated George Foreman grill. It was used approximately 8 years ago for 3 or 4 times to make meat hamburgers. It has not been used since then. I was going to grill vegetarian hamburgers, and I was wondering if these would be considered meat? Additionally, can I eat these vegetarian hamburgers with dairy together?
ב"ה Shalom 24 hours after the meat hamburgers were made on the grill, are sufficient time to allow you to eat your vegetarian hamburgers made on this grill , on dairy dishes and even to have the vegetarian hamburgers together with dairy. (רמ"א יור"ד סי' צה:ב) If the vegetarian hamburgers had been made on the grill within 24 hours of the meat hamburgers, you would be allowed to eat the vegetarian hamburgers on dairy dishes but to not to eat them with milk. However, you would be allowed to have milk immediately after eating them , and you not have to wait 6 hours after the vegetarian hamburgers. However, even in a case which the meat grill had not been used for 24 hours, there are still those who say that you may not grill your vegetarian hamburgers or other pareve items on this grill, if your intention is to begin with to later eat the vegetarian hamburgers with dairy. (חכמת אדם מח:ב, ספר הכשרות פרק י :צה) In regard to making the Teflon grill kosher or no longer meaty, since the grilling is done with no fluid, it would require the Teflon grill to be made kosher through the process of "libun". Libun is the process of bringing the utensil to the highest temperature by direct contact with fire. Many Rabbis feared that a person would not do so in fear of ruining the Teflon coating, and therefore do not allow the koshering of teflon (ספר הגעלת כלים יג:203, פסקי תשובות סי' תנא: לה , הערה 188) All the best