Taken from an article in Kovels' newsletter: Applies to the Comet/Authenticast lead plane models.
"Lead rot" is a problem for owners of lead soldiers and other lead toys. The main symptom is gray dust covering the toys. If it is not removed, the lead will eventually disintegrate. It is not contagious, but it's caused by storing groups of soldiers together, especially if they're stored in new wooden boxes. Store the toys in metal boxes. Keep all lead toys away from children. Nibbling on them can cause lead poisoning.