They may work, and could be the best thing if they have isopropyl alcohol in them!
From the X's manual for the UltraLeather White material:
Polyurethane Seats
Wipe spills as soon as possible using a soft cloth moistened with warm water and nondetergent soap. Wipe gently in a circular motion. For difficult stains on ultra-white seats, use isopropyl alcohol, then wipe with a damp cloth. After cleaning, allow the seats to air dry.
Edit: All the Premium seats are now the same material now, if that wasn't clear! The White, Black, and Cream.