Bouquet garni (those fancy little herb bouquets for flavouring soups and stocks) are usually wrapped in cheesecloth or muslin bags for easy removal once they have made their tasty contribution. That's all well and good, but there is a washable, reusable vessel for your little flavour packets and it is the common tea ball.
Given that a tea ball is around ten bucks, I don't know why you wouldn't use one for such savoury infusions. You can pack them with the classic parsley stems/thyme/bay leaf combo, or try something a little different, maybe lemon grass with some ginger and lime leaves?
The beauty of the tea ball is that you'll never have to "run out real quick to get some cheesecloth," leaving you free to try endless combinations.
Quick Tip: Use Tea Balls To Flavour Soup [The Kitchn]