How do I peel garlic in bulk?
Good ol' Chef John has a solution right here.

Basically, you want to enclose your garlic in some kind of container that lets them move around fairly easily. He uses two bowls, a commenter suggests a jar, I suppose it depends on the number of garlic cloves you want to peel. 

Close the container then start shaking away, maybe for 20-30 seconds or longer once you get the hang of how long this method takes for your chosen clove count.