Peroxide works just fine on all copper/brass relics in removing encrusted DIRT, it does not really remove the blue/green corrosive growths, only if the blue/green is a light coating, not raised bumps, nor does it remove patina, patina only comes off if the coin is corroded beneath the detail, sort of like exfoliated type of corrosion.
Following all cleaned using peroxide, not all my best samples, a good overview of some of the results. All are usually soaked afterwards in distilled water for a few hours, then dried thoroughly and then coated with either Blue Ribbon Coin conditioner or wax.
Don