[Unsolved]Knobs on my virus feel like they scrape when turned

[Infinity+1]

Hiya folks,

On my virus some of the knobs feel like they scrape a little when I turn them. It's an 8 month old Classic which I haven't really used heavily and it shouldn't be dirty.

Is there a possibility this might be because it's new and the knobs take time to 'break in'? The cutoff1 knob is fine, maybe because it's the most used? Some other knobs are fine too.

I've looked at the knobs from an angle and none of them touch the casing, they all jut out a couple of milimeters.

Someone told me it's possible to pull the knobs off and clean them... I tried to pull them lightly but there was no sign of them coming off and I certainly don't want to force them. Is this possible?

Any help is apreciated, thanks