Im assuming you dont have a bottle tree or rinser/vinator. I woul just sanitize the with a new spray bottle filled with a k-meta solution consisting off 3 tbls of k-meta to 1 gallon of hot water. Goto a dollar store and get a spray bottle just for this and cleaning other wine making equipment like spoons and hydrometer. If you dont want to spend the money though just mix up the k-meta solution in your primary and pour some into 1 bottle and just keep pouring to the next bottle and let each bottle drip dry. The bottles dont really have to be dry though so if theres still a few drops in there dont worry as it will actually help preserve the wine and dont worry that you already added k-meta to your wine as you are still nowhere near commercial amounts.
I use a bottle brush to scrub the inside of the bottle. Ifill a sink with warm water and add betadine solution to the water.there are 2 types of betadine,do not use betadine soap,use the scrub solution as it does not make bubbles. Rinse until clear x4,then put all bottles in dishwasher,DO NOT ADD SOAP.run the cycle and let dry .seems to work