Cosplay

A wash can help. Thin some dark brown paint with a thinner and brush it liberally over the gold, but try to concentrate it in the crevices and low spots. Using the right thinner is important. Water for acrylic can work OK, but isn't ideal. Distilled water is better than tap water. Acrylic medium or flow medium is better still.

Some people use mineral spirits and oil based paint to good effect. Other people prefer ink washes. Experiment on some test pieces to see what you like. It requires patience and a little experience to get it.

your caat doesn't look that enthused either

Gold leaf, Can't get more real than real. I've always been told that you should put a red base under gold leaf, but I don't know if you really need to.

I would recommend Rub ‘n’ Buff. They make really good colors and you can get the uneven tones that make a piece more realistic. They even have rust effect ones if you want to go there (great for crevices).

Tried the "hammered" spray paint options? Thank me later.

Way I tend to do metal look on stuff I 3D print is cover it in glue/lacquer, then blow either actual rust powder or graphite powder all over it.

And then apply the iron/gold/silver/whatever paint over it.

I use an undercoat of Vallejo Black Brilliant Undercoat and then spray with one of their golds

Put some mini shader on what you already got.

I do it with a chrome base and a yellow tinted clear on top.