Another member has a thread about a leather couch
with urine on it right now, but no solutions. Hissy mentioned in an old thread
that leather can be a smell cats try to cover with their own mark.
I personally, don't have any advice. A more careful search of the forum might find more, and maybe someone will post here with some advice. My general advice would be to look at your regular urine-cleaning product's label, or the label of anything you try. I don't think there is an "inconspicuous" part of a baseball glove to test, unfortunately.