Reply to Knob stiffness!

Ok..

This isn't a smutty porn spam message...

I've noticed that some of my VCI rotaries are much easier to turn that others, which are much stiffer. I'd like to get them all about the same.. has anyone got any ideas on how to loosen them up a bit ?

Even the loose ones are much stiffer to turn that the rotaries on my DJM-600.