Does anyone have a good starting point for engraving or annealing polished brass tags?

Our church has some brass tags on their oil decanters that look fairly terrible. I've done some raw/scrap brass on my 30W before and figured it wouldn't be much of a problem so I volunteered to make some new ones before the holiday season. Anywho, I got the polished brass tags in last night and I was only able to run a few tests (100mm/s, 100% power, tried at 30 and 80 kHz with a 0.01 hatch or thereabouts. Tried slightly out of focus initially for annealing, but didn't pan out) and I was surprised at how faint of a marking the laser left at those settings. The polished surface sure makes a big difference from the scrap brass I ran a while back. For kicks and grins I also Sharpie-d the surface and gave it another go, but same result-- faint markings.

I do plan on running through a proper test grid when I get a chance tonight or later this week (my "day job" keeps getting in the way), but I wanted to reach out and see if anyone here had past experience or tips as I move forward. I did have the foresight to purchase a spare tag-- so I do have the real estate to run some tests.

Thanks!