Since I am new at cleaning coins with a tumbler, I attempted to do so a couple different ways.
At first I used water, white vinegar and salt along with aquarium gravel. (I kept the water level just above the gravel / coins then added salt and vinegar.) I would run the tumbler for an hour then change out the water and refilled with the same mixture. I did this three times. This method removed a ton of crud off the wheaties and regular pennies.
I also used straight vinegar and salt with no water. This mixture didn't make much of a difference, so I went back to water, White Vinegar and salt.
I then used 2 lbs of 1/8" stainless steel ball bearings for a 4th run on the wheat pennies. Next, I filled the container with water(just over the stainless steel ball bearings and coins) and added a few drops of Dawn Dish detergent. I then let it run for a good hour. These pictures are the results. I feel the 4th run with the stainless steel media is a good way to end the cleaning. As you can see not every coin comes out nice. I may need to give it more time in the tumbler to get the stubborn coins clean.