what is the best way to removed the faded rear decal?

 

'Search' function is your friend, ..., 'Center taillight', 'polish' or 'polished', ..., etc., ...
Follow the directions & you should acheive what you're looking for.
Motorized tools will complete this job much faster than by hand also.

Start with nail polish remover to get rid of leftover red/pink paint.
Then wet-sand, then polish.
And Welcome a'board', ...


Edit added:
(From some of my previous posts, ...)


I've done literally DOZENS of these things over the last couple years, ...

Yes, nail polish remover will remove the leftover red fading ink first.
I start with a 600 grit, keeping it wet, using a small 1/4 sheet sander.
Then on to 1200-1500 by hand, then finish by hand with 2000 grit, keeping them wet while sanding to wash away the contamination.
Then I use an old Black & Decker orbital polisher with Zaino's Glass Polish first,
You'll get the same/similar description by most anyone else who has done it. Although some may not put that much work into it, .... You can also use other brands of polish. I've tried others, but didn't get the same quality results as I do with the Zaino process.

Good Luck!

(By the way, I do all this with the units screwed down to my temp workbench work surface. Not on the car.)

And yes, you can buy them from GM without the text/bird, or even other colors of the text/bird already. But they'll cost ya a lot more depending on the style you want.

All from GmPartsDirect.com
Firebird tail filler panel (from 93-97 Firebird V6) = 5977293---------------------$105.60 w/s&h&tax
Firebird tail filler panel (from 93-97 Formula) (plain black - no logo) = 5977294--$102.13 w/s&h&tax
Firebird tail filler panel (from 94 25th Anniv TA) (white logo) = 5977296--------- (Not available anymore)
Firebird tail filler panel (from 93-94 Trans Am) = 5978095----------------------$100.72 w/s&h&tax
Firebird tail filler panel (from 95-97 Firebird 3800 GT V6) = 5978095-------------$100.72 w/s&h&tax
Firebird tail filler panel (from 95-98 Trans Am) = 5977286-----------------------$95.65 w/s&h&tax
Firebird tail filler panel (from 99 Trans Am) = 5978095--------------------------$100.72 w/s&h&tax
Firebird tail filler panel (from 99 30th Anniv TA) (white logo) = 16525477--------$97.70 w/s&h&tax
Firebird tail filler panel (from 00-02 Trans Am) = 5977286 ----------------------$95.65 w/s&h&tax
Firebird tail filler panel (from 02 CETA) (silver logo) = 10312725-----------------$108.09 w/s&h&tax


And for decals, I'd also recommend,
bfranker.badz28.com/vinyl/vinyl.htm