Video creator Rescue & Restore who brings rusty, worn vintage toys back to their original shine and luster, quite skillfully took a rather dingy, discolored Millennium Falcon toy from 1978 with water damage and brought it back to it’s original, gleaming condition. The restorer paid a great deal of attention to each and every detail, including the replacement of a tiny mirrored Jedi training ball that was a crucial part of the interior.
The shell had yellowed with age from UV light exposure. I reversed the yellowing with a process known as RetroBright. If you submerge the plastic parts in hydrogen peroxide and add powerful UV lights, it will reverse the yellowing.