Faded/Discoloured grey plastic on stored Star Wars Vehicles

Could someone help with a bit of advice on faded Star Wars Vehicles. We unpacked a couple of AT-AT's yesterday that have been in storage for over 20 years. They had been in sealed bags but when we unwrapped them various sections of the grey plastic, mainly on the legs had changed colour! Some parts had almost change to olive green whilst other bits had gone darker grey.

The clear chin laser cannons had gone brownish on the ends. does anyone know how to get them back to their original colour again please?

Cheers

Ian

If you do a search for Vintage Rebellion Podcast one of their previous episodes had a discussion and guest on this subject. It's plastic degredation and from what I can remember happens for a number of reasons which they discuss. Unfortunately I don't think there's any coming back from it with a lot of plastics because it's not on the surface, it's changes in the chemical structure of the plastic itself :wink:

I was the guest on the Podcast on this subject. It's oxidation causing cross-linking of the Carbon bonds which weakens the structure and makes it change colour. UV and sunlight isn't only cause - a major cause is elevated temperature. A rule of thumb is every 10 degree Celsius rise in temperature doubles the rate of reaction. High temperatures even in the absence of UV is a killer for ABS and acetate.

don't think you can get them back to the original grey