Little help please. We are still not due to open for a few weeks. One of the lines has been used for Cider and the keg is now empty. I need to clean the lines and do not have a replacement keg for that line. We have extra cold Glycol coolers and have been told to turn off coolers before cleaning due to freezing. Is there a product that I can leave in the line for a week or so before the next clean as water seems a no no? Thank you.