Some years back I won a wash bucket full of Meguiars products in a raffle. It had an interior cleaner and detailer included. I don't remember the exact name of the product, but it worked pretty well. Generally, Meguiars products are pretty good.
Since then, I've found a product called UV2 Protectant. It doesn't dry out the vinyl like ArmorAll and the shine lasts for months when applied to the hard interior surfaces of the Fiero, including the steering column. One of the areas I find hardest to keep clean is the vent louvers. I spray UV2 onto a small foam paint brush and brush the inside of the louvers.