I used. One 600ml bottle of distilled white vinegar; two pieces of pure nickel; some copper wire left over from a house re-wiring project; salt; old plastic soup carton saved from the re-cycling bin; an old phone charger 5v 1a. Total cost of new items £5.
And it worked reasonably well! It was a bit fiddly but it worked.

Drawing about 220ma at 4v

Initial setting up, turning clear vinegar into green electrolyte by plating a nickel cathode from a nickel anode.

Parts in the electrolyte waiting for power on.

Comparison before and after.
The initial trial was with two untarnished washers, they came up really bright.
Fresh out of the electrolyte the parts are disappointingly dull, but a few seconds with polish and they brighten up nicely.




