I just finished a frag tank for a buddy of mines. It took a while to get a good routine down. They do make acrylic scratch temover kits that come with a foam pad and different grits. From 400 to 20000.
If recommend using a firm foam pad to get an even buff.
I started with 800 focusing in the heavily scratched areas,
Then i did all panels, both the inside and out side evenly in a horizontal stroke, followed by a vertical stroke using the foam pad with sandpaper to buff the surface evenly.
I did this from 1500 to 20000 grit.
After, i hit it with nuvo #3 for deep scratches then nuvo #2 for the fine scratches.
The Outcome ;
Pm me if you have any questions.