What will soften rubber parts?

[bushyb]

What will soften rubber parts?

I am looking to soften rubber gaiters that go between the fairing and the shocks. The bike has stood for a number of years; it runs great so I don’t want to strip it at all.
The fairing gaiters are of the vulcanized black rubber type. I am looking for a easy to use house / garage product that I can use to soften the rubber up and stay that way.
I have read elsewhere of a number of possibilities but would like to hear if someone has any experience with this or is a bio chemist who can recommend a cocktail to rub on the rubber to soften it and keep it that way with say maybe a maintenance period of every 3 months or so.
Hope you can help, thanks.