Which of these is the best choice:
"He was beaten with bibles."
or
"He was beaten with Bibles."
My take is the lowercase "bibles" is most appropriate because in this case, the term "bibles" is speaking about the objects, not "the Bible" as a text. That is, it's functioning as a common noun.
Thoughts?
EDIT: No, the linked-to discussion specifically doesn't deal with plurals, so it doesn't help.