Stumbled across an article from 2006 that claimed that Joe Strummer recorded parts for a song called "Janky Holocaust" intended to be on Chinese Democracy that was ultimately shelved.
I do not remember ever hearing this story at the time so wondering if anyone else has any more details?
In other news, ContactMusic.com is reporting that late THE CLASH rocker Joe Strummer contributed guitar for "Janky Holocaust", a track recorded for the long-awaited GUNS N' ROSES album "Chinese Democracy", two weeks before his death. Rose has since reportedly ditched the tune from the finished album.
Source: https://blabbermouth.net/news/axl-rose-sighted-at-the-allman-brothers-band-gig-in-new-york
Source: https://www.contactmusic.com/joe-strummer/quotes