Rant: I used to think you had to clean every rock you found in the field
For years, I'd bring back samples from places like the Black Hills and scrub them with a toothbrush and mild acid, thinking that was the 'right' way. I changed my mind last fall after a trip to a shale outcrop near my home. Cleaning a piece removed all the tiny fossil fragments that made it special, turning it into just a plain gray rock. Now I only clean stuff if the dirt is hiding key features, and even then I'm super careful. How do you all decide what to clean and what to leave alone?
You mentioned scrubbing rocks with mild acid. That's a strong step. What kind of acid were you using, and how did you learn that method? I've seen people ruin good specimens by going straight to acid when a soft brush and water would have shown them enough to stop.
Oh man, I feel called out. I totally jumped to acid once and learned my lesson the hard way, kind of like what jason_stone59 said. Sometimes you just get excited and skip the basics, you know? Now I always try the simple stuff first.