On cleaning, the "Universal" way of doing it, as per the Universal instructions, is to run a wad of fresh bread through it when you are finished grinding. Then rinse with warm water. That's all the instructions say.....but I'd think that if you broke it down to wash and dry it, you should be fine. I'm using the food grade silicone spray on mine. Oils can go rancid over time. If it's dry, there shouldn't be too much to rust, so dry might even be better than oiled. The bread....slice of plain white or better yet, piece of Texas toast (fresh) could also be used at the beginning to get some of the black out.
My Universal #2 didn't come with any nut butter plates. The OVB and KK did:

Cutters on top are from the Universal. Nut Butter plate is from the OVB. Other plate is from the KK, but is exactly the same. When I tried the nut butter plates, the openings in the cast body clogged and the crank was incredibly had to turn. I almost lifted the grinder off the board it was clamped to. Maybe you have to dribble them in vs. filling the hopper? And what came out was more like paste or meal than butter. But just plain nuts ground to butter don't look like peanut butter in the store anyway. It quickly separates into solids and liquids (oils).
I was able to use the butter plates for coarse cracking black pepper (leave them loose), as did the choppers on the Universal. The small cutters gave me a fine grind (not dust, but fine), while the middle gave me mix of coarse and fine. With the middle cutter, some whole corns came through. Again, hard to turn with those.
On the other meats and vegetables, this is what they look like from a food chopper:

This was through the OVB. The vegetables were mostly course chopped 1/2" chunks, and look more flailed than clean cut like you would get with a sharp kitchen knife. Ground leftover turkey on the left came through the round hole plate (pellets). Ground leftover turkey in the middle came through the finger cutters and looks shredded. Not the most appealing in appearance, but for this stuff, it's incredibly fast. There is probably no faster way to chop/mince a couple of onions (after you cube them up so they will drop into the screw slots).
If you are going to chop pork butt or other red meat with sinew and fat, you are supposed to tighten the nut down to the point the handle is hard to turn. Those cutters have to shear the sinew, which ain't easy. Partially frozen helps. Meat will "bloom" or "explode" out past the cutters. Not the best long term solution, but no reason you can't give it a try.