I do, and here's how I do it. I take the old potting soil, put it in a 3 gallon pot, and pour a kettle of boiling water through to kill it, then I mix it half and half with new potting soil. Things grow very well in this, and I've never had any root rot problems from the old soil.
Didymo (Didymosphenia geminata), also known as rock snot, is a non-native invasive microscopic algae (diatom) that can produce large amounts of stalk material to form thick brown mats on stream bottoms.
Dido. Daughter of king Belus of Tyre whose brother Pygmalion killed her husband Sichaeus. She escaped to North Africa with her people, and bought land from the native king Iarbus. On the land she founded Carthage where she became queen but killed herself when Iarbus threatened with war if she did not become his wife. Another version says that she fell in love with the Trojan prince Aeneas who had been shipwrecked outside the coast of Carthage after fleeing his sacked city. He left her later to go to Italy, where he became the founder of Rome, and the heart-broken Dido committed suicide.