The ceramic proton conductors (e.g. BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ, noted as BZCYYb) in protonic ceramic electrochemical cells (PCEC) exhibit high ionic conductivity at reduced temperature due to lower activation energy. However, high sintering temperature (≥1400 ^oC for BZCYYb, ≥1500 ^oC for BaZr_0.8Y_0.2O_3−δ) was required to densify these ceramic electrolytes during fabrication. The formation of well-annealed electrolyte surface because of the high sintering temperature leads to poor bonding between the electrolyte with oxygen electrode. Here, we proposed a novel and simple acid treatment method to rejuvenate protonic ceramic electrolyte surface. The acid etching process was after the full sintering of half-cell at 1400 ^oC. 0.3 mL concentrated nitric acid was used to etch the surface of dense electrolyte (for 10 mm button cell) before integration with oxygen electrode. We observed the obvious electrochemical performance improvements with different oxygen electrodes including PrNi_0.5Co_0.5O_3−δ, La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ, PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ and even with Pt or Ag electrode after acid etching. Large cells (5×5 cm², 10×10 cm²) with electrolyte treated by nitric acid was prepared and showed enhanced electrochemical performance as well.