I use full strength vinegar because you can reuse it. I have a lot of powerheads, so I just do them all on the same day, every 3-4 months. I use a one quart take out container from a deli, half full with vinegar. I put it next to the tank and lift the powerhead over the rim and set it running in the cup. The heat from the motor makes the vin work better too I think. After a half hour I move the cup to the next powerhead. I unplug the finished one and disassemble it, if it's really grody I bring it to the kitchen sink and spray it with the sprayer there, otherwise I just wipe off the impeller and pull the hairs off the fan part where they get tangled around it and put it back in service. If you keep regular maintenance it's never that hard to clean them. I don't bother rinsing, a little vinegar isn't bad for the tank.