Clean Machine "swooshing" noise

[gsgtrman]

Hi to all,
I recently built my own Clean Machine using a layout from Dragonfly (http://aronnelson.com/gallery/album14/CLEAN_MACHINE_LAYOUT_CORRECT). Since it was my first project and I have limited knowledge, I did not deviate from the schematic. The pedal does everything I want it to, and was a very enjoyable project to do. The problem that I am experiencing is that if I have the pedal activated, it makes a rather audible "swooshing" noise as I adjust the volume control. I realize that this is not that big of a deal, as I will find the control's sweet spot at the beginning of the evening and then leave it there, but I would also like the pedal to perform flawlessly if possible. Any suggestions?
Thanks for your help and insight,
George (gsgtrman)

[Dragonfly]

spray the pot with conatc / electronic cleaner. it sound like you have a dirty pot.