A little help. The " Livery " taste is due to blood remaining in the meat, and our modern palates just not being used to eating bloody meat. I happen to like liver, cooked medium rare when its fresh, so it remains pink, and tender, and sweet.
However, with game animals- from Wild Board to venison, to ducks and geese- it helps to soak the meat in water with vinegar added to it. You don't need much to change the PH balance to acidic, and that will draw the blood out of the meat. I can't tell you a specific amount of time. I want the meat to look as pale as what I am used to buying wrapped in plastic, to be very honest. Liver is suppose to be strong tasting; other meat isn't! to my way of thinking!
I also don't like meat that tastes like vinegar! So, after getting the blood out of the meat-- this can take a couple of soakings over several hours-- I then soak it in cold water to get the vinegar out of the meat. I suppose a bit of sugar in the water might help get that done, but I would not go overboard with the sugar. I am talking about 1/4 cup of sugar for a kitchen sink full of water!
As long as the meat is soaking in cold water you don't have to worry much about spoilage. Just do this out of direct sunlight, and preferrably indoors.
I like to age my game when its from an old and tough bird, or beast. I put the meat, after the soaking, dried off with paper towels, in crocks, and large pans, covered, in the refrigerator, for a week. I rotate and rinse the meat and pans twice a day each day for those 7 days. This allows the meat to age, and for the enzymes in the connecting tissues, and meat, to break down the connecting tissues and tenderize the meat. If I could figure out how to rig a UV or Black Light inside my refrigerator to light up the meat, I would do that, too. Then the meat would tenderize in about 3 days instead of 7. After 7 days, the meat is ready to eat, or store.
In process of removing the blood and other strong tastes from birds like geese and ducks, any mud flavor in the meat is also removed. That makes much better fare, and can make it worthwhile to actually go out and hunt the birds. In the Midwest, where we don't exactly have access to a lot of saltwater, we have that muddy taste problem with several species of duck, and White and Blue Geese. I have even heard some people complain about the taste of Canada Geese, but I have smoked, and wet roasted those, and never tasted any " mud ". The meat is dark red, and tastes more like beef to me than to any other fowl I have eaten. I have eaten both wild and domestically raised duck, and like them both when they are prepared correctly. The domestic duck you buy frozen at your supermarket tends to be sweeter eating because of the corn the birds are fed to fatten them.