Copper plating, is sulphuric acid necessary? Alternative to H2SO4?
Copper acetate can be used, at least for a thin layer, and it can be made with chemicals found at home.

To get a bright copper coat, extra acid (vinegar, 5% acetic acid, in this case) or gelatin can be added.

That said, if the plating is for through-hole continuity, it might be simpler and cheaper to use a solderable conductive ink.