Serious question, had a chat with a retired FAA inspector at the Oshkosh airshow that made me pause.
He said, 'We never wrote up a plane for being too clean, but we sure did for not being clean enough.' Made me rethink my entire pre-inspection wipe-down routine. How thorough is your cleaning before you start signing off?
That bit about grime hiding problems is exactly right. I spent an extra hour once just wiping down an engine bay, and it showed a tiny fuel weep I would have completely missed. Now I treat the rag and solvent as the first inspection tool out of the box. A clean surface tells you the truth.
That quote about cleaning being the first step of inspection is spot on... but I'd push back a tiny bit on calling it a 'spotless' plane. You don't need it spotless, just clean enough to see what's actually there. Overcleaning can actually hide things too if you're not careful with solvents and rags.
That quote hits hard because grime hides problems. A spotless plane lets you see every crack, seep, and worn spot you might miss otherwise. It turns cleaning from a chore into the first real step of the inspection.