Ah! Two different jobs! The best solvent I know of for black powder is water, but that won't get you anywhere with the lube. I bet you'd like to find a lube solvent that also happens to work on black powder.
I doubt it will work on synthetic lubes, but mild soap is great for the olive oil, crisco, tallow and mink oil grease lubes I've used.
Okay, I'll quit messing with you. I just use water with a little bit of dish soap in it. I'd experiment with it on your particular lube first, then look for something else water soluble that will attack your particular lube.