Gently polish the pen with a sunshine cloth, or a microfiber cloth and some polish. I am not sure which readily available polishes are best, but Flitz fro an auto store, or polish for silverware should do fine. It will almost certainly clean up easily and look great when you are done. Be Gentle!
I do not want to throw a wet blanket on you..... But.......
I would say these are at best $80 (once they are restored) on the open market, when you have no reputation regarding the quality of repair, and no way for buyers to know if you stand behind the pen and the work done on it. Ebay advanced search for completed sales shows Wahl 0 pens selling for: $40, $52, and $17.39 (with 4 bids on the cheap one). But a Buy It Now sold for $79.99, restored with a writing sample showing that the nib was flexible.
If you are planning on selling, you might do better just making it shine and selling unrestored. A lot of us can put new sacs in pens, so there is not always as much of a price increase for restoration as you might hope.
Finally, the market for ringtop pens is not that great, and a Wahl 0 baby ringtop is a "cute" pen but not a pent that people chase.