I am going to offer a more permanent solution I adopted after drilling the primer pockets of Starline .445 brass for rifle primers.
Involves more work but only needs to be done once.
Get a small letter punch or 2.
Think I got these at Brownells or Sinclair.
For the rimmed brass I used a length trim die (I had never used) mounted
upside down in the top of the press to hold the brass.
Then locate the letter(s) on a blank area of the base and tap with a hammer.
Presto. A semi-custom headstamp only you have.
Pic gives an idea how this can look.
I realize this may not be too practical for the auto brass but
thought I'd toss it out anyway as another method of marking brass (for good).
I do also use the magic marker method brought up above.
In addition, I have used stickers with the load written on them pasted on the base of 12ga. shells.
Kind of wary of that last one as bits of sticky paper can work their way into the firing pin holes.
Snapcaps with spring loaded brass "primers" can also leave brass bits in the firing pin hole and bushing.
These can usually be blown out with air or solvents.