I have put some thought into the topic as I have sold off some of my copper, brass & aluminum scrap over the last couple years or so.

Never thought about the thinness of the aluminum fins and it not being easy to process into new metals.
What about aluminum cans? they seem about the same thickness as the aluminum fins around/on the copper tubes.

I have read that aluminum foil is not a popular scrap item because they say that it just mostly burns away in the furnace.
Must have something to do with the processing of the materials before they are fed into the melt.

I have noticed that most of the aluminum fins that I have ended up with that are separated from the copper do smash a bit differently then cans when you step on a pile with your feet to compact it. But then it was bent and crumpled sheet v.s. cylinders with ends and a air release hole.

Must be more expensive and require more steps and processes for foil and thin fins then aluminum cans that have been sorted, cleaned and compacted or such?

I have read that aluminum cat food cans are another item along with used cooking foil that many yards don't want to MESS with. But it seems that it is the MESS that they want to avoid as aluminum foil is most times very dirty. As for cat food cans, not just sure what the problem is there beyond being dirty with paper labels and such. Are they a different aluminum or thickness then soda and beer cans are made of? It's all such a puzzle.

I will cut the magnetic metals away or out of these type items. And I will most times cut the easy to get at extra copper or such off for a better overall return.

I have been getting a very nice pile of old copper/aluminum bearing items together as I find them around the yard. Still have many items to move later that I can see but not easily get at until I clear the areas around them better.

Seems that more research is required on the differences in aluminum materials that cans, foil and thin sheet are made from and what must be done to process into a final product.

Where is Mister Rogers and Picture Picture when you need them?