I've been a little nuts over 40's and 50's basic JLC's lately. This one arrived from France. It was supposed to be a working bumper but it appeared DOA. I planned to take it to my Watchmaker and get a revision and the hands cleaned up . It was in a jiffy bag in my safe and fell out and started working- So I decided to wear it just for today to monitor timekeeping. I looked inside when it arrived and although the dial has signs of moisture, the movement, apart from being filthy seems just fine. I suspect the drop might have loosened some rust buildup in the sub second pinion.
I've recently seen a members JLC on WRUW where he said he carefully cleaned the dial just with water and it came up brilliantly. Of course I can't find it now....Anyone have experience with removing rust spots on this type of JLC dial?
I'm also including the picture of a French twin (minus a lug) to a 469 I have..just cos!!
Thanks for any advice..

 

A very wise man (and extremely experienced watchmaker) once said on these forums:

"clean a dial only if you're prepared to destroy it".

Of course, you may have a great result, or you may not.

But be prepared.

 

I have cleaned a few dials with water only, but It have also ruined several doing that... I would recommend to try a drop of water on one spot before going anyfurther.

 

I read somewhere of a water, lemon juice mixture that worked very well, but of course can't find it now.
I suppose depending on cost you could find a parts watch and change it out.