Seriously though, is cleaning a grinder that big of a deal? A brush takes like 30 seconds and you're not throwing out a perfectly good potato or a slice of bread. Seems like solving a problem that doesn't really exist.
Read about a deli that uses a small piece of potato instead of bread. The starch helps clean out the fat and bits, and you can see when it comes out clean. Seems like a solid trick if you're out of old bread. Might even work better with the potato's texture pushing everything through.