Milk Tank Preheater?

[Brokermike]

As i was taking apart a bulk milk tank that I bought I came across the thin wall copper cooling system used in the tanks. It is thin wall copper and very flexible, it is also prebuilt in a preheater configuration (though bigger than I need at 3'x9').

Does anyone know what used to be pumped through the copper? Was it milk or some sort of antifreeze? The tubes are empty and dry now, with no odor.

[maplecrest]

freon is my guess

[maple flats]

Yes, some type of freon. You should not try to use it for sap.

[WESTVIRGINIAMAPLER]

Should bring a nice $$$ scrap, so shop around and find the best price and take the proceeds and should buy quite a bit towards building a preheater.