I've done this before, but not with as much effect as today. That is using mineral oil on the dash and other plastic bits. I found an old bottle of heavy mineral oil ( USP, laxative) and applied it fairly generously to the dash. Let it sit a spell then buffed off. Did a nice job. But what really pleased me was how it restored the chalky door handles and handbrake cover. I have the self destructing brown plastic in my van and nothing I have used on it before has been quite as good as the mineral oil.

Alistair