Someones lying...

[thecatspajamas]

Zack Hample's book "The Baseball" has a good write-up of an interview he did with one of the clubhouse personnel who was responsible for rubbing up balls before the game (don't have the book with me, and can't recall which team). The gist of it is that, although the same mud is used consistently, there can be inconsistencies depending on who is rubbing up the ball and which balls are selected for game use. When the ball was pulled (or hit) from play can also have an effect on how "dirty" it appears, and for sure balls nowadays are pulled much more quickly than in Ruth's day.

I'm not sure if these factors would account for one ball being "filthy" and another "near pristine", but you would expect at least some range of "dirtiness" rather than a consistent level of "dingy" in the overall scheme of things.