Wood Wax Before And After Photo Proper Cleaning Of Wood Door Surface Before Painting.?

Proper cleaning of wood door surface before painting.? - wood wax before and after photo

I'm going to paint the dark wood doors in my house. The doors are cheap plywood (on internal policies, not "good") wood, but they are painted white to match the wood.

I want to finish the surface clean (with a lacquer or a kind of mini-Wax "poly" zone) to the debris that has collected in recent years, clearly. (I know it's there to see, but not really.) During the first door with Kilz and Valspar primer before painting with latex, semi-gloss.

How do I clean it?. Alcohol, mineral?