I should have thought of this sooner: if you have a tea ball, you can use it to hold seeds and herbs for easy removal when making soups.
Above, I've (temporarily) removed the chain that hangs over the lip of the mug and filled my tea ball with green cardamom pods, black peppercorns, and cloves. Granted, you may want a bigger tea ball for larger batches of soup than my single-serving one in the photo. But for the Thai oxtail soup recipe I was following, this worked out fine.
The other tip I wanted to relate was that if you're aiming for a clear soup and have bone-simmering involved, keep the heat low and simmer gently. When the water boils, knocking the bones about, the soup turns out cloudy.
And below's the final result (with me customarily forgetting the final garnish, celery leaves this time, before shooting). Recipe was good, but I think a touch sweet. Probably a little too much cinnamon.