18d ago

The guy who runs the pawn shop on 8th showed me his CLA trick and I'm still not sure about it

The soap itself isn't what's doing the work there, it's the fact that he's using it in warm water and rinsing it all off right away. Plain Dawn or whatever won't strip a modern hard coating, sure, but a lot of those old Pentax Takumars and even some K mount glass have softer coatings that can go cloudy over time from repeated exposure to alkaline stuff. What probably saved his hide is that he's not scrubbing, just dunking and rinsing, and he's not letting it sit. The haze he was fighting was likely fungus or old lube offgassing, and plain water alone would've knocked most of that back anyway. Try that same trick on a 60s Leica or a Canon FL lens with a soft coating and you might get a different result.