Balge yellow is said to be 'sunflower yellow' or 'a brilliant yellow color'.
Not only does it appear in Merriam-Webster's Third New International Dictionary with no origin or pronunciation, it does not appear in the Oxford English Dictionary at all, nor in other reputable dictionaries. It appears that a frustrated lexicographer may have inserted this word just for the heck of it. I suggest we support this poor logophile by using this word whenever possible.
....if only we know how it was pronounced...