A couple SEM questions.

Would you use the vinyl prep or the Plastic and leather prep on the armrest part of the door panel?

I've got a can of each but they're both maybe 15 years old. The shelf life for the spray cans is 3 years under ideal conditions, but the shelf life for the brush on stuff is indefinite. I've tested my cans and they still spray good. I wonder if the product has really gone bad? I've also got the soap (new), and I'm wondering if it is even necessary to use the preps with the soap.

Now I can answer my question with a list of things not to clean the interior with -

90% rubbing alcohol strips the paint.

SEM Soap strips the paint.

Vinyl Prep strips the paint.

The good news is there's no need to buy anything more expensive than 50% rubbing alcohol. I learn these things the hard way so you don't have to.