My gel patina only discolored my brass piece instead of darkening in the crevices.
Liver-of-sulfur does not do much of anything to brass, but works great on copper and silver. To add an "antique" finish to brass, I've found that Birchwood Casey's Brass Black works well. It's available at most gun shops and sometimes even Walmart. Here's a link: http://www.walmart.com/ip/Birchwood-Casey-15225-Brass-Black-Touch-Up-3oz/23237826