There has been some discussion on restoring old slot cars. Here are some pictures and tips on restoring a vintage body that has been well used. Hope this helps.
The damage is mainly on the rear.
Disassembly.
Cleaning with dishwashing soap and Ronsonol lighter fluid.
Crease is worked out mainly with fingers and sometimes pliers.
Flex glue and Insta-Set (kicker) used to repair cracks. The ends of the cracked pieces are aligned and glued. The kicker makes the glue dry instantly. Then the rest of the crack is glued together. The kicker is applied to the area with a plastic stick instead of being sprayed on.
Ready for touch up paint and decals.
To help unwarp the sides of the body, Rick and I stretch the body out on a wood block. Sometimes heat from a hair dryer is applied, while pressing the body against the block helps flatten the body.