Homebrew PCBs

I find it hard to follow the complete threads here so forgive me if I 
am repeating something.

If the question was how to prevent copper boards from oxidizing, you 
can coat them with a layer of electronic style soldering flux. Some 
PCB manufacturers supply bare boards that way: there is no corrosion 
on them and they take solder very readily. This type of flux has no 
acid and can be left on the boards after assembly. I have seen boards 
with 20 year old flux on them and there was no sign of any problems from it.

Of course, tin plating looks nicer. You can also solder plate them. 
This has been done with a combination of chemical plating with the 
individual metals and then heating them to melt them together into a 
solder alloy.