A wise, if regretful decision. I used a pH meter regularly years ago. I recall that the probe end, when not dipped in test samples, must be stored in a solution of chemicals. I think that it's merely a buffered mix of ionic solutes that can be easily rinsed off in water, but i'm uncertain.
I also wonder about pathogens developing in a biofilm on the probe end. Any non-residual surfactant ( ie.: 3% hydrogen peroxide ) seems likely to damage the instrument.
I think it would be safer to take a small sample of the liquid in a cup, test it, and discard it after. Comments, anyone? I'm only speculating, and i never did understand the science that makes a pH meter function.
Best wishes on your next effort !