Any commercial polishing compound should do, for the smoothest pump stroke, get a soft spring combo, lube & break in the pump kit (don't lube if it's delrin), get an o'ringless bolt and polish the hammer (and the bolt if you can't get a delrin bolt)
I have a delrin bolt but it still has small orings. Also should I polish my ccm pump kits guide arm and pump arm? I also just installed the maddman spring kit so I got the lightest springs in right now, haven't had a chance to shoot it yet
If you want super smooth at the cost of efficiency, then take the o'rings off and use that bolt, I'd say polish the guide rod only if it feels gritty when you stroke, otherwise you run the chance of loosening the pump handle's tolerances without a noticeable difference in stroke (except for the handle wiggling about).