The best thing you can use to renourish seals is
1Z Gummi Pflege.
1Z einszett German Car Care Products - Plastic, Vinyl & Rubber Care, Cockpit Premium, Gummi Pflege
If you use Black Wow it would probably do more harm than good as its meant for hard plastics and would likely clog soft seals and eventually they would loose all moisture and turn hard and brittle.