Plastic Restorer - Revitalize Dry (Brittle) Plastic?

Hi Everyone,

I can't say how happy I was to find this forum and the amazing amount of information on here.

Problem:
I have found that some of my older 3rd party Plastic shells (xbox case, but more importantly Viper GC Case) are becoming dry and brittle due to:

Theory:
1. Most likely the quality of plastic used by manufacturer
2. Age (these are over 10 years old now

Current Situation:
I unfortunately lost one Viper GC Case that was never used and was installed and hit the open button once to test and the plastic that holds the spring for the lid just snapped right off. I have recently purchased another (due to the part being small and eventually lost) but wondered:

Question:
1. Is there a recommended product I can use to add the oils back into the plastic to bring it back to healthier conditions? ( example: stuff for plastic trim for cars?)