MIMF

Hi.

I live on the southeast coast of Australia. The piockup covers on my LP tarnished a lot very quickly - unimpressed, but that's not where I'm going - so recently I gave the whole guitar a good clean up set up etc & now the pickup covers shine like new...and I swear the guitar sounds different!! Happily much nicer..

so..

is it likely that tarnished pickup covers would effect the sound of a guitar?

Is it a nice, clean sound? No longer gritty? Sorry, couldn't resist...

It probably had more to do with the "set up, etc." you did rather than the clean up.
Although my late father-in-law was a mechanic and always said a clean car runs better. The implication was that you felt better about driving it anyway.

Did they happen to change the strings on that job?

A clean set of strings do change the tone instantly (over a rusty, old set). A clean pickup cover, I don't think so.

Well, rust forms a crystal lattice, and as anyone familiar with Alexander Dumble knows, tone can't exist in a crystal lattice. <g>

I always liked my own tone... but when I was a kid my mother never did.

She used to always say "I don't care for your tone young man".

Mine always said, "You'd better change that tone, young man, before I do it for you!"
That always worked, because I knew the tone she'd bring out would not be a good one.

To the OP, MHO is, new strings/setup, especially if you adjusted/changed pickup height while cleaning them or during setup.

The pickups will actually sound better if you remove the covers. The metal covers dull the tone and flattens the resonant peak due to eddy currents forming in the conductive surface. This is why people started removing the covers in the first place. Now that there is an on going retro fad, everyone wants covers on the pickups.

You could be about to put the whole "relic'd" industry out of business with a statement like this. Then again perhaps more on-shore jobs will be gained with the newly minted pickup polishing industry. We can only hope that the relic'd industry will come sweeping back into vogue right about the time the last pickup cover has been brightened to it's former glory. Ahhh progress!