Noisy pots when I turn them fast

[Tdale]

I'm rewireing my DC30, to get rid of the rats nest of wires.

There is some hum, but I hope I'll get rid of that.

The pots are quiet, but when I turn them really fast, there is a scratchy sound... Is that natural?

But is generally scratcy pots caused by DC-leackage? or dust/worn out pots?

Tommy