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.
The didgeridoo traditionally comes from the Northern Territory of Arnhem Land, Australia. In the NE Arnhem Land it is referred to as the 'Yidaki' and in Western Arnhem Land it is called the 'Mago.'.