My experiences clear coating brass is anywhere
you touch it after polishing your fingerprints will
appear under the clear after a short time. Wearing
gloves should solve that problem. The few times I
tried it didn’t hold up and removing it is a bigger
pain than just having to re-polish. Aluminum dulls
some when its coated and I had the same problem
with it holding up. You need a little texture (tooth)
for paint to adhere well so applying it to a perfectly
smooth surface is likely to lead to some kind of
problem over time. Not that long ago someone
posted that "Incralac Spray Lacquer" is what you should
use for brass. I’ve never tried it. Its a little pricy. I
did find it on the Wal-Mart website For $24.00 but
it doesn’t appear its available in their stores so your
going to have to add shipping. They want almost
$43.00 for it on eBay but they have another brand
for $29.00.

Every hobby I’ve been into has had aluminum to
polish and for well over 50 years of polishing that
crap I’ve tried a bunch of polishes.
The red (pink) polishes are some what abrasive to
help smooth the surface to bring back a shine but
you get the best (mirror) shine on a really smooth surface.
This would be an example and the first I tried in the early 60’s.
I have a buffer now and I’ve moved on. 😯

This stuff is made from a white rouge, the least
abrasive, and on an ideal surface will bring out
the best, brightest, mirror shine on a "smooth" surface.

This stuff is rather expensive but unlike most other
aluminum polish after you work it in and everything
is good and black stop and let is haze over. Then
just wipe it off like a car polish. Made with a green
rouge. Slightly more abrasive than white but less than
red. It the easiest way to bring back what a neglected
surface has to offer and what I used on the A-25 I
posted pictures of.

To preserve the shine rather than a clear coat I sometimes
I will use this. Its just a paste wax. They don’t offer
it for sale anymore but I suspect its just a carnauba
paste wax in a tube.