fix distortion in audio restoration project?

[EGS]

Hey all,

I've got an audio restoration gig, consisting of cleaning up several precious old out-of-print classical records. One in particular has brief moments of distortion at loud peaks. It is clean except for these peaks. This is not digital clipping, but rather an analog distortion present on the source. We've even been able to examined more than one (identical) LP pressings, and the distortion is present in the same spots on all.

How to fix?

My best solution - so far - is to use Izotope RX to manually select and lower the gain of the tiny bits of distortion, often working the frequencies in-between the music when possible. Sometimes this kinda sorta works...

Help!