Just a thought, but there's a chance it could be a lot of static build up. The only reason I'm bringing it up is that I recently bought the 60th Anniversary Impulse! boxset and experienced the exact same thing. On about three tracks there was distortion on higher notes at certain points in the songs in the right channel, even after running the brush over it. Thankfully, I have the original release for a couple of these tracks. Played those, no distortion. I assumed I got a bum pressing. But I did notice that the static build up when I opened the boxset was ridiculous. I had a real difficult time just pulling the discs from the sleeves (which were some kind of coated paper). So I gave all the discs a bath and washed them thoroughly....and the distortion disappeared. I put them back in some MoFi anti-static sleeves, haven't had a problem since. So I guess that's a long way to say, try giving it a good wash before you discard.