I would just throw them in the dishwasher with the heated dry option. Also, make sure that you are not using any detergent when cleaning them in the dishwasher. If there's still stuff on the inside, you may want to use a bottle brush to remove some of the debris. If it's still there after all of that, maybe another soak in an Oxyclean solution for 24 hours will do the trick.
"Brewers enjoy working to make beer as much as drinking beer instead of working."