1. Is it possible to make a Teflon frying pan only used once before Kosher for Pesach? 2. Can an electric cake mixer (stainless steel bowl and aluminum beater) be made Kosher for Pesach?
1. The rule is that we do not Kosher Teflon-coated utensils for Pesach because they are designed for use even without liquids such as oil, therefore their koshering is with Libun Chamur, but because Teflon utensils get ruined by Libun Chamur we fear he will spare them and not do Libun well. Nevertheless in this case because it was used only once, if it is known that it was used with liquids, it can be koshered by Hagalah. [ספר הגעלת כלים של הרב צבי כהן פרק יג סעיף רג והערה רטו, ספר הכשרות של הרב פוקס פרק ג סעיפים מ ונח ובהערות]. 2. It is preferable not to use this mixer for Pesach because the flour infiltrates through the slits in the head of the mixer, and it is hard to clean, and when it is used for Pesach some remnant of flour or dough may fall out. It is permitted to kosher it for Pesach by cleaning the head of the mixer well with strong detergent. The bowl and the beater should go through Hagalah. If it is possible to do a light Libun without it ruining, it is preferable to do so. [שו"ע ורמ"א סימן תנא סעיף יח וביאור הלכה ד"ה בפסח, ספר הגעלת כלים של הרב צבי כהן פרק יג סעיפים קמד ורכג ובהערות].