Problem with Postwar green paint on old Lionel accessories

Those look like rust spots coming from under the paint. Are your sure these bases were not repainted? I am not sure how rust forms under paint without a scratch or nick to the paint, but if the item was previously rusty and repainted, any remaining  rust prior to the repaint could continue to spread. 

I guess it is possible that they were repainted as I am no expert on these, but it looked original to me. Also like I had mentioned there are some similar spots on my 156 platforms which are Bakelite plastic. It is almost like a fading spot on the paint from sunlight, although if it were from the sun it should be over a large area and more uniform.

I have seen Lionel accessories with similar discoloration marks. Definitely original paint.

I never tried to figure out the cause.

I don't know the cause either, maybe mold? Anyway try some minimally abrasive auto polish like Nu Finish. 

Pete

Norton posted:

I don't know the cause either, maybe mold? Anyway try some minimally abrasive auto polish like Nu Finish. 

 

Pete

I tried some Mother's auto wax a little while ago with no effect at all. I believe that Mother's has a mild cleaner abrasive similar to what you described with the Nu-Finish. I guess this problem is just something I have to expect from that old green Lionel paint.

Maybe George called it. Not rust as these are diecast but a form of zinc rot if its coming through the paint???

Might require stripping the paint, somehow sealing the metal and repainting.

Pete

I don't think it's from oxidation of the metal underneath the paint because I've seen the same discoloration on gatemen, which have a sheet metal base.

I have found that any household cleaner with amonia or even Windex diluted with 50% water will cause this on original Lionel leaded paint. I have had a few unfortunate incidents until I figured it out. The problem does not seem reversible as the stain goes all the way through the paint.

Try gently rubbing some Lionel smoke fluid on it which is mineral oil. This works well with prewar paint

I concur with the idea that the discolorations are caused by liquid cleaners with any bleach/ammonia.  Whatever one uses to clean the green surfaces, it is vital to quickly wash the surface.  The spots mentioned as yellow stains are where drops of liquid cleaner remained without a good wipe down.  I have found that some of the yellow and cream colors show similar issues.