Alex is right about the old grease being a failure waiting to happen. These bikes are worth the effort and money it will take to make them rideable. (I wouldn't fool with the HUFFY.) After you've cleaned them and IF you don't feel confident enough to strip them down, then take them to a shop and let them do it for you. The bikes are worth it, and the enjoyment you will get from riding them properly set up will repay you several times over.