Homebrew PCBs

Hi there, I'm new to etching PCBs and to the group. 

Faced with some pretty tarnished copper clad I took the same approach
that I use for cleaning copper bottomed cookware, namely lemon juice
and a scotchbrite pad. Cleaned up all the oxidation very easily! Not
knowing if the lemon juice would leave any residue behind I finished
off by wiping the board with rubbing alchohol. 

Just wondering if anyone else has tried lemon juice and/or has any
thoughts on how suitable it is for cleaning copper clad pcb material.