Through pure luck I happened upon a huge tumbler. (I'd previously conducted Scientific Research with a ton of small tumblers of various types.) I learned that I didn't need to add the plastic BBs, aquarium gravel, or any of the other stuff I had messed with--just pennies, water, and the tiniest bit of soap or shampoo from the dollar store. The soap probably helps clean, but more importantly it adds a bit of lubricity to the whole mess. I tumbled them for about half an hour, then--this is important--I rinsed them repeatedly until I got no more suds. This Scientific Process preserved the patina of the coins; aquarium gravel or other tumbling media removed it.
I'd dump the coins into a mesh basket, and let the excess water drip off. The rinse water has chlorine in it, so I'd soak them in acetone 1) to rinse off the chlorine, and 2) acetone is said to kill verdigris. It's been awhile, but as I recall I'd soak them for about 15 minutes. The acetone will eventually absorb water and have to be replaced. This is why I'd let the excess water drip off as much as possible, but avoid letting the pennies dry out.
You'll have really ugly pennies if you just let them air-dry. Through pure luck (I lead a charmed life) I found a dual-tub jewelry polisher, and it came with a huge box of coffee bran--perfect for drying/polishing. I powdered some carnauba wax and added a tiny bit to the coffee bran. (Through pure luck I discovered a Magic Bullet at a yard sale. Works perfect for this.) I think the carnauba helps keep the coins from tarnishing even when carelessly stored in damp sheds and basements. It certainly makes them move smoother through the Ryedales as well as coin returns! I conducted Scientific Research with all kinds of ideas for drying, but the jewelry tumbler (you could use a Harbor Freight cement mixer) is the only idea that worked, and it worked well.
I was separating the pennies from the drying media by shaking them in a mesh basket, until I tore my rotator cuffs in an incident totally unrelated to penny sorting. Then through pure luck I stumbled upon a vibratory contraption that let me drop the media/pennies mixture onto a screen. The vibration lets the media fall through the screen into a hopper while the pennies dance to the exit end of the screen. It's louder than hell.
Now the coins are ready for the Ryedales. If your machine isn't clean as a whistle, clean it thoroughly. The powdered carnauba will eventually coat the hopper, wheel, and ramp with a thin slippery layer. You'll love it. Scientific Research suggests that powdered Teflon is no substitute for powdered carnauba.