So when I clean fryer there is always a bit of white bubbles on top of the fresh oil at first. It is a conola oil. the process I take. losen up the gunk and all the bad grease and drain.. next.. I drain it with water a few times to get the rest of the chunks out.. Then I fill the min line with water and put in a packet of Mr muscle. let boil for 15 min minimum. drain out rinse out a few times. then I dry while all the wet out. pit in new grease and was am white bubbles come up.