I removed all of the small brackets that hold the fiberglass rear panels in my fastback in order to repaint them. This was mostly done to remove any/all rust and to P/O the screws. Yah, they are hidden but ...
I had originally scribed numbers onto blue tape along with markings as to which end was up.
However, when media blasting and painting this no longer worked or I had to only do a few in order to not mix them up.
Since my wife does a lot of plant propagation, she also has many plastic tags onto which she either prints or hand writes plant details.
I took a few dozen and put a hole on one end using a hand held leather punch.
I then used plant wrap wire -- twist tie material -- and made a long loop.
The handy spool, as shown below, has a built in cutter too.
Mark the tag on both sides with details, such as number order or placement.
Media blast using the tag as a holder. Or, dip in Evapo-Rust using the tag or twist tie to loop over the edge of the container. If you are doing many items in a bath make the loops long enough and the same length so that you can suspend all of them using a rod across the container.
Blow it off (or rinse) and use the tag in order to hold for painting.
Leave the tag and put the item on the shelf for easy identification later.
Be sure to mark both sides so that paint or media doesn't accidentally remove your one and only identifier.