So,
While working on my Revan hilt I had a happy accident and discovered a VERY cool effect that can be done with gold leaf.
Normally you would apply the gilding adhesive and wait about 15-30 minutes for it to seal in and get "tacky". But, if you want to go for a rubbed down/worn brass look, here's what you do.
Apply your gilding adhesive along the area. Immediately apply your gold flake.
Let it sit for about 30 seconds, and then using your finger start to rub it flat and press it hard into the hilt. Most of the flake will wear away and flake off but you will be left with a VERY thin amount along the hilt that looks just like a polish was worn down to a brass colored metal underneath.
You can see this technique on the lower part of the hilt in this picture. The picture doesn't do it justice though. I haven't tried this with a different colored flake, but I was imagine similar effects would be achieved with other alloy or precious metal flake