Let you're friendly bacteria eat it. That's what they're there for. If you still see uneaten food an hour after you feed, maybe a circulation problem. I have tons of messy eaters, probably over-feed, have no scavengers and never chase down uneaten food. I do have a homemade tool to stir the substrate once in a while, but that's it. In my FOWLR tanks, uneaten food is gone within 1/2 hour--max.
I'll learn something here; I'm not an eel person nor do I keep gobies in my FOWLR tanks; Aren't most gobies potential lunch for any moray eel?