Couple Questions On Wires

Hey guys my brother and I are from southern VT and we're trying our hand at scrapping. Really don't know much about this business, but there isn't **** out there for jobs so we figure lets make our own right?

I have a couple question about wires. We have a bunch of insulated wires (is it still considered insulated with only electrical tape around it?) that are a mixture of copper and alum, do they have to be separated? They can be difficult to tell apart sometimes. Also should the ends me cleanly cut or does that matter at all? And Christmas lights are separated into their own category?

Thanks For Any And All Help Guys & Gals,
Sam