Immersion in a peroxide solution was found to increase electrical conductivity in p-GaN. Auger electron spectroscopy, current-voltage, and Hall measurements were used for characterization. All samples in this study were grown on the c plane of sapphire substrates by molecular beam epitaxy using solid Ga and ratio frequency plasma-activated Na source with a hole concentration of 1.1 x 10(17) cm(-3). The samples were first cleaned in boiling aqua regia (3 HCl + 1HNO(3)) for 10 min, rinsed in de-ionized (DI) water, and blown dry with N-2. Metal contacts (2 nm Ni/100 nm Ti/100 nm Au) were deposited with an electron beam evaporator (< 10(-5) Torr). After metal deposition, samples were immersed in a H2O2 solution (1H(2)O(2):5H(2)O or 1H(2)O(2):1H(2)O) for different time (30-300 s). This was followed by a DI water rinse, a N-2 blow dry and a short dry in 80 degrees C air. For a treatment of 1H(2)O(2):1H(2)O for 300 s, a similar to 100% increase of conductivity was observed. Hall data showed that the carrier concentration increased by 70% after these treatments. X-ray photoelectron spectroscopy data showed Ca 3d and O is bond energies were increased by H2O2:H2O treatments. The increased conductivity was speculated to result from reduction of compensation of Mg accepters.